Homemade Raspberry Rhubarb Crumble Pie

I didn’t grow up eating rhubarb, so when I first saw those bright pink stalks at the farmers market, I honestly had no idea what to do with them. My neighbor swore by her grandmother’s rhubarb pie, but it always came out too tart for my kids to finish.

That’s when I learned the secret: you need to balance rhubarb’s sourness with something sweet. Raspberries do exactly that, plus they add natural pectin to help everything set up nicely. And instead of choosing between a double-crust pie or a fruit crisp, this recipe lets you have both—a buttery crust on the bottom and a crunchy oat topping on top. It’s become my go-to spring dessert.

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What Kind of Rhubarb Should I Use?

Fresh rhubarb is your best bet for this pie, and you’ll find it in grocery stores during spring and early summer when it’s in season. The color of the stalks can range from pale green to deep red, but don’t worry – the color doesn’t affect the flavor, so either will work perfectly fine. When you’re shopping, look for firm, crisp stalks and avoid any that feel soft or look wilted. If fresh rhubarb isn’t available, you can use frozen rhubarb instead – just make sure to thaw it completely and drain off any excess liquid before adding it to your filling, otherwise your pie might end up too watery.

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Options for Substitutions

This pie is pretty forgiving when it comes to swapping ingredients around:

• Raspberries: You can use strawberries, blackberries, or a mix of berries instead. Just keep the total amount of fruit the same – about 18 ounces or 3 cups.
• Rhubarb: Fresh or frozen rhubarb both work great here. If using frozen, don’t thaw it first – just add it straight to the filling. You might need an extra tablespoon of tapioca to handle the extra moisture.
• Instant tapioca: If you don’t have instant tapioca, use 3 tablespoons of cornstarch or 1/3 cup of all-purpose flour as a thickener. Mix it well with the sugars before adding to the fruit.
• Old fashioned oats: Quick oats can work in the crumble topping, though the texture won’t be quite as chunky. Don’t use instant oats – they’ll turn mushy.
• Cardamom: Not a fan of cardamom? Try using vanilla extract (1 teaspoon) or stick with just the cinnamon and ginger for a simpler spice profile.
• Lime zest: Lemon zest works just as well and gives a similar bright citrus note to balance the sweetness.

Watch Out for These Mistakes While Baking

The biggest mistake with this pie is skipping the 15-minute rest for the fruit filling – this step lets the tapioca start absorbing the juices, which prevents a runny, soupy pie that won’t slice cleanly.

Another common error is using warm butter for the crumble topping, which will melt into the flour instead of creating those nice chunky pieces, so make sure your butter is cold and cut it into small cubes before working it in.

To avoid a soggy bottom crust, place your pie on a preheated baking sheet (as the recipe suggests) and consider brushing the crust with a beaten egg white before adding the filling to create a moisture barrier.

Finally, resist the urge to cut into the pie right away – that 4-hour cooling time isn’t just a suggestion, as it allows the filling to set properly so you get clean slices instead of a fruity mess on your plate.

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What to Serve With Raspberry Rhubarb Crumble Pie?

This pie is pretty amazing on its own, but a scoop of vanilla ice cream on top takes it to the next level – the cold creaminess is perfect against the warm, tart filling. If you’re not an ice cream person, a dollop of fresh whipped cream or even some tangy Greek yogurt works great too. I love serving this for summer gatherings with a pot of coffee or some iced tea on the side. For a fun brunch idea, try pairing a slice with your morning coffee and some scrambled eggs for a sweet and savory combo that actually works really well together.

Storage Instructions

Store: Once your pie has cooled completely, cover it loosely with foil or plastic wrap and keep it in the fridge for up to 4 days. The crumble topping might soften a bit in the fridge, but the flavors actually get better as they meld together overnight.

Freeze: You can freeze the whole pie or individual slices for up to 3 months. Wrap it tightly in plastic wrap, then in foil to prevent freezer burn. I like to freeze slices separately so I can grab just one whenever a craving hits.

Serve: Let frozen slices thaw in the fridge overnight, or at room temperature for a couple hours. If you want to crisp up that crumble topping again, warm individual slices in a 350°F oven for about 10 minutes. It’s amazing served with a scoop of vanilla ice cream!

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 2500-2700
• Protein: 23-28 g
• Fat: 80-92 g
• Carbohydrates: 420-450 g

Ingredients

For the crust:

• 1 pie crust (Pillsbury recommended for a consistent flake)

For the crumble:

• 3/4 cup old fashioned oats
• 1/2 cup all-purpose flour
• 1 cup brown sugar, firmly packed
• 3/4 tsp salt
• 1/2 tsp cinnamon
• 1/4 tsp ginger
• 7 tbsp unsalted butter, melted and cooled

For the filling:

• 4 cups rhubarb, cut into 1/2-inch thick slices
• 18 oz fresh raspberries
• 1/4 cup brown sugar
• 1/4 cup granulated sugar
• 1/3 cup instant tapioca, finely ground
• 1 lime, zested and juiced
• 1/2 tsp cardamom
• 1 tsp vanilla extract

Step 1: Prepare the Pie Crust and Make the Crumble Topping

• 1 pie crust
• 3/4 cup old fashioned oats
• 1/2 cup all-purpose flour
• 1 cup brown sugar, firmly packed
• 3/4 tsp salt
• 1/2 tsp cinnamon
• 1/4 tsp ginger
• 7 tbsp unsalted butter, melted and cooled

Roll out your pie crust to about 12 inches in diameter and transfer it to a 9-inch pie pan, letting the edges hang slightly over the rim.

Place it in the freezer while you prepare the crumble topping.

In a medium bowl, whisk together the oats, flour, 1 cup brown sugar, salt, cinnamon, and ginger until evenly combined.

Drizzle the melted and cooled butter over the mixture and use a fork or your fingertips to work it in until the mixture resembles coarse breadcrumbs with pea-sized clumps.

Transfer the crumble topping to the refrigerator to chill while you work on the fruit filling.

Step 2: Prepare the Fruit Filling and Let It Macerate

• 4 cups rhubarb, cut into 1/2-inch thick slices
• 18 oz fresh raspberries
• 1/4 cup brown sugar
• 1/4 cup granulated sugar
• 1/3 cup instant tapioca, finely ground
• 1 lime, zested and juiced
• 1/2 tsp cardamom
• 1 tsp vanilla extract

Combine the rhubarb, raspberries, 1/4 cup brown sugar, 1/4 cup granulated sugar, finely ground instant tapioca, lime zest, lime juice, cardamom, and vanilla extract in a large bowl.

Gently fold everything together until the fruit is evenly coated with the sugar and tapioca mixture.

Let this sit at room temperature for 15 minutes—this allows the tapioca to absorb some of the fruit’s natural juices and helps prevent a soupy filling.

I find this resting time is crucial; it prevents excess liquid from making the crust soggy.

Step 3: Assemble and Bake the Pie

• pie crust from Step 1
• fruit filling from Step 2
• crumble topping from Step 1

Preheat your oven to 400°F and place a baking sheet or piece of foil on the lower rack to catch any drips.

Remove the chilled crust from the freezer and pour the macerated fruit filling directly into it, spreading it evenly.

Scatter the chilled crumble topping from Step 1 evenly over the fruit, breaking up any large clumps as you go—don’t pack it down, as you want it to stay loose and crispy.

Place the pie directly on the preheated baking sheet and bake for 45 to 55 minutes, until the crumble topping is golden brown and the fruit filling is bubbling slightly at the edges.

I recommend checking around the 40-minute mark; if the crumble is browning too quickly, you can tent it loosely with foil for the remaining time.

Step 4: Cool and Serve

Remove the pie from the oven and let it cool at room temperature for at least 4 hours before slicing.

This cooling time allows the filling to set properly so it slices cleanly instead of running all over the plate.

The pie can be served at room temperature or slightly warmed, and it’s wonderful with a scoop of vanilla ice cream or a dollop of whipped cream on the side.

Homemade Raspberry Rhubarb Crumble Pie

Delicious Homemade Raspberry Rhubarb Crumble Pie recipe with step-by-step instructions.

Print Recipe Pin Recipe

Prep Time 35 minutes mins

Cook Time 1 hour hr 10 minutes mins

Total Time 1 hour hr 45 minutes mins

Servings 8 slices

Calories 2600 kcal

Ingredients

  

For the crust

• 1 pie crust (Pillsbury recommended for a consistent flake)

For the crumble

• 3/4 cup old fashioned oats
• 1/2 cup all-purpose flour
• 1 cup brown sugar, firmly packed
• 3/4 tsp salt
• 1/2 tsp cinnamon
• 1/4 tsp ginger
• 7 tbsp unsalted butter, melted and cooled

For the filling

• 4 cups rhubarb, cut into 1/2-inch thick slices
• 18 oz fresh raspberries
• 1/4 cup brown sugar
• 1/4 cup granulated sugar
• 1/3 cup instant tapioca, finely ground
• 1 lime, zested and juiced
• 1/2 tsp cardamom
• 1 tsp vanilla extract

Instructions

 

• Roll out your pie crust to about 12 inches in diameter and transfer it to a 9-inch pie pan, letting the edges hang slightly over the rim. Place it in the freezer while you prepare the crumble topping. In a medium bowl, whisk together the oats, flour, 1 cup brown sugar, salt, cinnamon, and ginger until evenly combined. Drizzle the melted and cooled butter over the mixture and use a fork or your fingertips to work it in until the mixture resembles coarse breadcrumbs with pea-sized clumps. Transfer the crumble topping to the refrigerator to chill while you work on the fruit filling.
• Combine the rhubarb, raspberries, 1/4 cup brown sugar, 1/4 cup granulated sugar, finely ground instant tapioca, lime zest, lime juice, cardamom, and vanilla extract in a large bowl. Gently fold everything together until the fruit is evenly coated with the sugar and tapioca mixture. Let this sit at room temperature for 15 minutes—this allows the tapioca to absorb some of the fruit's natural juices and helps prevent a soupy filling. I find this resting time is crucial; it prevents excess liquid from making the crust soggy.
• Preheat your oven to 400°F and place a baking sheet or piece of foil on the lower rack to catch any drips. Remove the chilled crust from the freezer and pour the macerated fruit filling directly into it, spreading it evenly. Scatter the chilled crumble topping from Step 1 evenly over the fruit, breaking up any large clumps as you go—don't pack it down, as you want it to stay loose and crispy. Place the pie directly on the preheated baking sheet and bake for 45 to 55 minutes, until the crumble topping is golden brown and the fruit filling is bubbling slightly at the edges. I recommend checking around the 40-minute mark; if the crumble is browning too quickly, you can tent it loosely with foil for the remaining time.
• Remove the pie from the oven and let it cool at room temperature for at least 4 hours before slicing. This cooling time allows the filling to set properly so it slices cleanly instead of running all over the plate. The pie can be served at room temperature or slightly warmed, and it's wonderful with a scoop of vanilla ice cream or a dollop of whipped cream on the side.