Apple Rhubarb Pie with Crumb Topping

by Haley // July 21, 2023

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Combine the tart flavors of rhubarb with the crisp texture of apples to make this delicious apple rhubarb pie. The oat crumb topping is perfectly buttery and crunchy!

side of apple rhubarb pie slice showing layers.

One of my favorite desserts is apple crumble pie. When I saw fresh rhubarb at the store, I knew I had to toss some in to my next pie! The tart flavor and bright colors add a new layer of deliciousness.

Table of Contents

Why You’ll Love This Recipe

Easy to make. You can use store-bought pie crust for easy prep (or make your own crust ahead of time). The filling and topping comes together in minutes!
Great use of in-season ingredients. Take advantage of having fresh rhubarb during the early summer or freeze it and use it when apples are in season in early fall!
Comfort food. The aromas of a freshly baked pie filling the kitchen is simply the best.
Perfect for any occasion! Whether it is the Fourth of July, Thanksgiving or a late summer evening with friends, you can enjoy this pie any time of the year.

Ingredient Notes

bowls of ingredients to make apple rhubarb pie.

Apples: Use a crisp apple, such as Granny Smith or Honeycrisp. The texture will withstand the heat of the oven. Peel, core and slice before using.
Rhubarb: Fresh rhubarb will provide the best flavor, but frozen may also be used. Cut into 1/2-inch pieces.
Pie crust: Use either homemade or store-bought crust. If using my homemade pie crust recipe, you will only need one piece of dough (save the other for another recipe, like my pecan pie).
Oats: Rolled oats, also known as old-fashioned oats, make the crumb topping chewy and flavorful.
Butter: Use cold unsalted butter cut into 1/4-inch pieces. It has to be cold in order to get the right texture for the topping.
Spices: Check that your spices are fresh and not expired for the best flavor!

Refer to recipe card for ingredient details and measurements.

Recipe Variations

Add some chopped nuts. You can add nuts to either the filling or the topping (or both!) Roughly chop about 1/2 cup walnuts or pecans. Stir in with the apple rhubarb ingredients or whisk in with the dry ingredients for the topping.

Add some berries. Just like my strawberry rhubarb crisp, this pie tastes delicious with berries! Add 1/2 cup diced strawberries or raspberries to the filling ingredients.

Make a top crust. Use a second crust to drape over the filling. Crimp the edges and slices a couple holes in the center to release steam. Alternatively, you can make a lattice pie top like I do for my cranberry apple pie!

Serve with vanilla ice cream or a dollop of fresh whipped cream. I think a drizzle of caramel sauce would also taste delicious!

How to Make Apple Rhubarb Pie

Make the filling: In a large bowl, toss together the apples, rhubarb, sugar, flour, spices and lemon juice.
Make the crumb topping: Whisk together the dry ingredients, flour, oats, brown sugar, sugar and cinnamon. Use a pastry cutter to cut cold butter into the dry ingredients.
Assemble: Transfer filling to chilled crust. Add crumb topping and press down slightly.
Bake pie at 400° F for 20 minutes, then decrease the temperature to 375° F for 30 to 40 more minutes.

Expert Tips

Chill the pie crust. In order to get a flaky pie crust, make sure the dough is cold. I always put my dough in the pie plate first and keep it in the freezer while preparing the filling and topping.

Prepare the rhubarb properly. Remove the leaves and ends of stalks, then wash under cold water. Cut the stalks into slices no smaller than 1/2-inch pieces. Remove any brown spots as you slice.

Use cold butter. This is super important for the oat crumble! If the butter is too warm, then it will melt into the filling as the pie bakes and the topping won’t be as crisp and crunchy.

Keep an eye on the pie while it bakes. After about 30 to 40 minutes of baking, check that the crust isn’t browning too quickly. If it is, put a layer of aluminum foil loosely over the top until done baking.

Let the pie cool completely, about 4 hours, before slicing. This is really important if you want the slices to be clean and structured. I usually wait a full 6 hours before cutting.

unsliced apple rhubarb pie with crumb topping next to fresh apples and rhubarb.

Make Ahead and Storage Tips

Make ahead: The crumb topping may be made ahead of time and stored in an airtight container the refrigerator for up to 48 hours. If making your pie crust from scratch, it may also be kept in the refrigerator for 48 hours. Make sure it is tightly wrapped with plastic wrap to prevent it from drying out.

Storage: After the pie has cooled, cover it and store in the refrigerator for up to 5 days. It is good to serve chilled, at room temperature or reheated.

Freezing: After the pie has cooled, wrap the entire plate with plastic wrap and aluminum foil to prevent freezer burn. Freeze for up to 3 months. Defrost in the refrigerator overnight.

Reheating: Preheat oven to 350 F. Remove any plastic wrap and place a layer of aluminum foil over the pie. If chilled, reheat for 10 to 15 minutes or until heated through. If frozen, increase baking time to 20 to 30 minutes.