There is something truly magical about the moment your fork breaks through a buttery, crisp topping to reveal a bubbling, vibrant fruit filling. If you love sweet and tart flavors mixed with cozy textures, this berry crumble oatmeal pie is about to become your new favorite treat.

Welcome back to Angie Bloom! I am so excited to share this recipe with you. Whether you want to impress guests at a weekend dinner or just need a comforting dessert on a Tuesday night, this pie delivers. It perfectly bridges the gap between a traditional fruit pie and a rustic fruit crisp. Best of all, it uses simple ingredients you probably already have in your freezer and pantry.

Let us dive into why this mixed berry crumble stands out from other easy berry pie recipes, and exactly how you can bake it to perfection in your own kitchen.

The following content may contain affiliate links. When you click and shop the links, we receive a commission.

Why Choose a Frozen Berry Dessert?

Fresh berries are wonderful when they are in season, but they can be expensive and hard to find during the colder months. That is where the beauty of a frozen berry dessert shines. Frozen berries are picked and flash-frozen at their peak ripeness. This means they lock in all that gorgeous summer flavor and vital nutrients.

Using frozen blueberries and blackberries makes this recipe incredibly convenient. You do not have to wait for July to roll around to enjoy a spectacular pie. Just grab a couple of bags from your freezer, let them thaw, and you are halfway to a phenomenal dessert. The juices from the thawed berries mix with sugar and cornstarch to create a thick, jam like filling that holds its shape beautifully when sliced.

The Magic of the Mixed Berry Crumble

The true star of this dessert is the contrast in textures. Traditional double crust pies are delicious, but they miss out on the incredible crunch that an oatmeal crumble provides.

When you bake this pie, the bottom crust turns flaky and golden. The berry filling transforms into a sweet, slightly tart, juicy masterpiece. Then comes the topping. The blend of old-fashioned oats, brown sugar, and unsalted butter crisps up in the oven. The result is a delightfully crunchy crown that complements the soft, warm berries perfectly. The addition of fresh lemon peel in the topping adds a bright, citrusy note that cuts through the richness of the butter and elevates the entire flavor profile.

If you have been searching through easy berry pie recipes hoping to find something unique but uncomplicated, this is exactly what you need.

Here are a few other recipes from the blog that everyone loves:

Greek Lemon Turkey Soup

Protein Packed Asian Beef Bowl

Flavor Packed Chicken Buddha Bowl

Stuffed Red Pepper Soup

Spicy Coconut Lime Chicken Soup

The Best Taco Soup

Sausage Low Carb Italian Soup

Mexican chicken Salad

Ingredients for Your Berry Crumble Oatmeal Pie

Gathering your ingredients is a breeze. Here is exactly what you need to create this masterpiece.

For the Berry Filling

2 cups frozen blueberries: Unsweetened and thawed. They bring a deep, sweet flavor and a beautiful purple-blue hue.
2 cups frozen blackberries: Unsweetened and thawed. These add a wonderful tartness and robust texture.
1/2 cup sugar: Granulated white sugar works perfectly to balance the tartness of the berries.
3 tablespoons cornstarch: This is your thickening agent. It prevents the pie from becoming a soupy mess.
1 tablespoon lemon juice: Freshly squeezed is best. It brightens the flavors of the berries.
1 pie crust: You can use a store-bought unbaked crust for convenience or make your favorite homemade dough.

For the Oatmeal Crumble Topping

3/4 cup all-purpose flour: The base of your crumble.
1/2 cup light brown sugar: Packed tightly. The molasses in brown sugar adds a deep, caramel-like sweetness.
1/2 cup old-fashioned oats: These provide the signature crunch. Avoid quick oats if possible, as they can become mushy.
1 tablespoon lemon peel: Freshly grated. This secret ingredient ties the topping to the filling beautifully.
1/2 cup (1 stick) unsalted butter: Cut into small pieces and brought to room temperature so it blends easily with the dry ingredients.

Step-by-Step Baking Instructions

Ready to bake? Follow these simple steps for a foolproof pie.

1. Prepare Your Equipment and Crust

Begin by preheating your oven to 350°F (175°C).

Take your pie crust and gently press it into a standard 9-inch pie dish. Crimp the edges however you like. If you are using a homemade crust, make sure you chill it in the refrigerator while you prepare the filling. Keeping the crust cold ensures it stays flaky during baking.

2. Mix the Berry Filling

Make sure your frozen blueberries and blackberries are fully thawed. Drain any excess liquid so your pie does not get soggy.

In a large mixing bowl, combine the thawed blueberries, thawed blackberries, sugar, cornstarch, and lemon juice. Toss everything gently with a large spoon or spatula. You want to coat the berries evenly with the sugar and cornstarch without mashing them.

Pour the berry mixture directly into your prepared, unbaked pie crust. Spread it out into an even layer.

3. Create the Oatmeal Crumble Topping

In a separate medium-sized bowl, mix the all-purpose flour, light brown sugar, old-fashioned oats, and grated lemon peel. Stir these dry ingredients together until they are well combined.

Add the room-temperature butter pieces to the bowl. Use your clean hands or a pastry blender to work the butter into the dry mixture. Keep mixing until the topping resembles coarse crumbs. You want distinct, pea-sized clumps of buttery oats and flour.

Sprinkle this crumble topping evenly over the berry filling in your pie dish. Make sure you cover the fruit completely, going all the way to the inner edge of the pie crust.

4. Bake to Perfection

Place your pie on the middle rack of your preheated oven. Bake at 350°F for exactly 35 minutes.

You will know the pie is done when the oat topping turns a gorgeous golden brown and you can see the berry filling bubbling thickly around the edges.

Pro Tip: If you notice the edges of your pie crust browning too quickly during the baking process, loosely tent the edges with a strip of aluminum foil.

5. Cool and Serve

This is the hardest part of the entire recipe: waiting. Remove the pie from the oven and place it on a wire cooling rack. Allow the pie to cool for at least two hours before slicing. Cooling gives the cornstarch time to fully set the fruit juices. If you cut into the pie while it is piping hot, the filling will run everywhere.

Easy Berry Crumble Oatmeal Pie Recipe

Yield: 6

Author: Angie Bloom

Prep time: 15 MinCook time: 35 MinTotal time: 50 Min

Looking for a delicious frozen berry dessert? Try this easy berry crumble oatmeal pie featuring juicy berries and a buttery, crunchy oat topping.

Cook modePrevent screen from turning off

Ingredients

2 cups frozen blueberries
2 cups frozen blackberries
1/2 cup sugar
3 tablespoons cornstarch
1 tablespoon lemon juice
1 pie crust

Oatmeal Crumble Topping

3/4 cup all-purpose flour
1/2 cup light brown sugar
1/2 cup old-fashioned oats
1 tablespoon lemon peel
1/2 cup (1 stick) unsalted butter

Instructions

Begin by preheating your oven to 350°F (175°C).
Take your pie crust and gently press it into a standard 9-inch pie dish. Crimp the edges however you like. If you are using a homemade crust, make sure you chill it in the refrigerator while you prepare the filling. Keeping the crust cold ensures it stays flaky during baking.
Mix the Berry Filling - Make sure your frozen blueberries and blackberries are fully thawed. Drain any excess liquid so your pie does not get soggy.
In a large mixing bowl, combine the thawed blueberries, thawed blackberries, sugar, cornstarch, and lemon juice. Toss everything gently with a large spoon or spatula. You want to coat the berries evenly with the sugar and cornstarch without mashing them.
Pour the berry mixture directly into your prepared, unbaked pie crust. Spread it out into an even layer.
Create the Oatmeal Crumble Topping - In a separate medium-sized bowl, mix the all-purpose flour, light brown sugar, old fashioned oats, and grated lemon peel. Stir these dry ingredients together until they are well combined.
Add the room-temperature butter pieces to the bowl. Use your clean hands or a pastry blender to work the butter into the dry mixture. Keep mixing until the topping resembles coarse crumbs. You want distinct, pea-sized clumps of buttery oats and flour.
Sprinkle this crumble topping evenly over the berry filling in your pie dish. Make sure you cover the fruit completely, going all the way to the inner edge of the pie crust.
Bake to Perfection - Place your pie on the middle rack of your preheated oven. Bake at 350°F for exactly 35 minutes. You will know the pie is done when the oat topping turns a gorgeous golden brown and you can see the berry filling bubbling thickly around the edges. Pro Tip: If you notice the edges of your pie crust browning too quickly during the baking process, loosely tent the edges with a strip of aluminum foil.
Cool and Serve - This is the hardest part of the entire recipe: waiting. Remove the pie from the oven and place it on a wire cooling rack. Allow the pie to cool for at least two hours before slicing. Cooling gives the cornstarch time to fully set the fruit juices. If you cut into the pie while it is piping hot, the filling will run everywhere.

Recommended Products

Mixing Bowl Set

Spatula

Nutrition Facts

Calories

547

Fat

24 g

Sat. Fat

12 g

Carbs

81 g

Fiber

6 g

Net carbs

75 g

Sugar

42 g

Protein

5 g

Sodium

125 mg

Cholesterol

41 mg

The nutrition information provided is only estimated based on an online nutritional calculator. I am not a dietician. Please consult a doctor for accurate, more personal information about your health and any dietary restrictions and concerns you may have.

Expert Tips for the Best Results

To make sure your dessert turns out perfectly every single time, keep these simple guidelines in mind:

Drain the berries: Frozen berries release a lot of water as they thaw. Strain them in a colander before mixing in the cornstarch. You do not want extra water diluting your filling.
Check your butter: Room temperature butter is crucial for the topping. If the butter is too cold, it will not mix well with the flour. If it is melted, your crumble will turn into a greasy paste. It should yield slightly when you press it with your finger.
Protect the bottom of your oven: Fruit pies are notorious for bubbling over. Place a baking sheet lined with parchment paper or foil on the rack directly below your pie to catch any rogue drips.

How to Serve and Store Your Pie

This mixed berry crumble pie is spectacular entirely on its own. The flavors are bright, rich, and comforting. However, if you want to elevate the experience, serve a warm slice alongside a generous scoop of vanilla bean ice cream. The cold ice cream melting into the warm, crunchy oat topping is pure heaven. A dollop of freshly whipped cream also works wonders.

If you have leftovers, cover the pie dish tightly with plastic wrap or aluminum foil. You can store it at room temperature for up to two days, or place it in the refrigerator for up to five days. To reheat, simply pop a slice in the microwave for 15-20 seconds, or warm it in a 300°F oven until heated through.

Bring This Recipe to Your Kitchen

Baking should be a joyful, stress free experience. This recipe proves that you do not need complicated techniques or out of season produce to create a show-stopping dessert. By relying on trusted pantry staples and freezer favorites, you can whip up an incredible treat whenever the craving strikes.

Gather your ingredients, preheat that oven, and enjoy the wonderful aroma that is about to fill your home. Let me know how your berry crumble oatmeal pie turns out! Happy baking from all of us here at Angie Bloom.

Remember that a healthy lifestyle isn't built on deprivation. It's built on discovery, nourishment, and finding joy in the food you eat. I encourage you to take this recipe, make it your own, and see how simple, clean ingredients can come together to create something truly satisfying. You have the power to write your own story of health, one delicious meal at a time.

We’d love to see your creations! Snap a photo, share it on social media, and tag us at @angiebloom. Have questions or want to share your favorite add-ins? Drop a comment below or connect with us via email.

If you're looking for more healthy recipes and cooking tips, be sure to sign up for our newsletter, here. Happy cooking!