This raspberry rhubarb slab pie is a vibrant, crowd-pleasing dessert that perfectly balances tart and sweet flavors. Baked in a large pan and sliced into bars, it’s ideal for gatherings, spring celebrations, or simply enjoying a homemade treat with family.
Why You’ll Love This Recipe
This recipe is perfect when you need a dessert that serves many people without extra effort. The combination of tangy rhubarb and juicy raspberries creates a refreshing flavor that feels just right for spring and summer. The slab format makes slicing and serving simple, and the buttery crust pairs beautifully with the fruity filling. It’s also versatile, allowing you to experiment with different fruits while keeping the same base technique.
Ingredients
(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)
For the crust:
3 3/4 cups all-purpose flour
1 1/2 teaspoons salt
1 tablespoon granulated sugar
1 1/2 cups cold unsalted butter, cubed
3/4 cup cold water
For the filling:
4 cups fresh rhubarb, chopped into 1/2-inch pieces
3 cups fresh raspberries
1 1/2 cups granulated sugar
1/3 cup cornstarch
1 tablespoon lemon juice
1 teaspoon vanilla extract
Preheat your oven to 190°C (375°F). Lightly grease a jelly-roll pan (about 10×15 inches).
In a large bowl, combine flour, salt, and sugar. Cut in the cold butter until the mixture resembles coarse crumbs.
Gradually add cold water, mixing just until the dough comes together. Divide into two portions, one slightly larger than the other.
Roll out the larger portion and fit it into the prepared pan, pressing it gently into the corners.
In another bowl, mix rhubarb, raspberries, sugar, cornstarch, lemon juice, and vanilla until evenly combined.
Spread the filling evenly over the crust.
Roll out the remaining dough and place it over the filling. You can leave it whole with slits or create a lattice pattern.
Mix the egg and milk, then brush over the top crust. Sprinkle with coarse sugar if desired.
Bake for 40–45 minutes, or until the crust is golden and the filling is bubbling.
Allow the pie to cool completely before cutting into squares.
Servings and timing
Servings: 12 to 16 pieces
Preparation time: 25 minutes
Cooking time: 45 minutes
Total time: 1 hour 10 minutes
Variations
You can easily adapt this recipe to suit your taste. Swap raspberries for strawberries if you prefer a sweeter flavor, or mix both fruits for added depth. A touch of cinnamon or ginger can give the filling a warm spice note. For a richer crust, you can replace a small portion of butter with cream cheese. You can also add a crumb topping instead of a top crust for a different texture.
Storage/Reheating
Store the slab pie covered at room temperature for up to 2 days or in the refrigerator for up to 5 days. To reheat, place a slice in the oven at 160°C (320°F) for about 10 minutes, or warm briefly in the microwave. For best texture, reheating in the oven is recommended.
FAQs
Can I use frozen fruit instead of fresh?
Yes, but thaw and drain it well to avoid excess moisture in the filling.
How do I keep the crust from getting soggy?
Make sure the filling is well mixed with cornstarch and bake until fully bubbling.
Can I make the dough ahead of time?
Yes, you can refrigerate the dough for up to 2 days or freeze it for longer storage.
What if I don’t have a jelly-roll pan?
You can use a similar-sized rectangular baking pan, though baking time may vary slightly.
Can I reduce the sugar?
Yes, but keep in mind that rhubarb is naturally tart, so reducing sugar will make it more tangy.
How do I know when the pie is done?
The crust should be golden brown and the filling should be visibly bubbling.
Can I add other fruits?
Absolutely, blueberries or blackberries work well with rhubarb.
Do I need to peel rhubarb?
No, just wash and trim the ends before chopping.
Can I freeze the baked pie?
Yes, wrap it tightly and freeze for up to 2 months. Thaw before reheating.
How do I get clean slices?
Let the pie cool completely before cutting to allow the filling to set.
Conclusion
Raspberry rhubarb slab pie is a simple yet impressive dessert that combines classic flavors with easy serving. Whether you’re baking for a gathering or just treating yourself, this recipe delivers a delicious balance of sweet and tart in every bite.
