Raspberry-Rhubarb Slab Pie is a sweet-tart dessert baked in a sheet pan, perfect for feeding a crowd. It features a buttery, flaky crust filled with a vibrant mix of juicy raspberries and tangy rhubarb, thickened with cornstarch and sweetened just enough to balance the fruit’s natural zing. Topped with a golden crust and finished with a drizzle of vanilla icing, this slab pie is ideal for spring and summer gatherings, potlucks, or any occasion that calls for a rustic yet elegant dessert.
Ingredients:
For the Crust:
- 3¼ cups all-purpose flour
- 1 teaspoon salt
- 1 cup cold unsalted butter, cubed
- ¾ cup 2% milk
- 1 large egg yolk
For the Filling:
- 2 cups granulated sugar
- ⅓ cup cornstarch
- 5 cups fresh or frozen raspberries (thawed and drained if frozen)
- 3 cups fresh or frozen rhubarb, chopped (thawed and drained if frozen)
For the Icing:
- 1¼ cups confectioners’ sugar
- ½ teaspoon vanilla extract
- 6 teaspoons 2% milk (adjust for consistency)
Instructions:
1. Make the Dough
- In a large bowl, whisk together flour and salt.
- Cut in the cold butter using a pastry cutter or your fingers until the mixture resembles coarse crumbs.
- In a small bowl, whisk together the egg yolk and milk.
- Gradually add the milk mixture to the flour, tossing with a fork until the dough just comes together. Add a little more milk if needed.
- Divide the dough into two portions, one slightly larger than the other. Wrap each in plastic wrap and refrigerate for at least 1 hour.
2. Prepare the Filling
- In a large bowl, stir together sugar and cornstarch.
- Add raspberries and rhubarb, tossing gently to coat. Set aside.
3. Assemble the Pie
- Preheat oven to 375°F (190°C).
- Roll out the larger portion of dough between two sheets of floured wax paper into an 18×13-inch rectangle.
- Transfer to an ungreased 15×10×1-inch baking pan, pressing the dough into the bottom and up the sides. Trim excess dough.
- Spoon the fruit filling evenly over the crust.
- Roll out the second portion of dough and place it over the filling.
- Fold the bottom crust over the edges of the top crust and crimp to seal. Prick the top crust with a fork to allow steam to escape.
4. Bake
- Bake for 45–55 minutes, or until the crust is golden brown and the filling is bubbling.
- Remove from oven and cool completely on a wire rack.
5. Add the Icing
- In a small bowl, whisk together confectioners’ sugar, vanilla, and milk until smooth.
- Drizzle over the cooled pie using a spoon or piping bag.
Tips & Variations:
- Fruit Options: Substitute strawberries or blackberries for raspberries if desired.
- Frozen Fruit: Always thaw and drain frozen fruit to avoid excess moisture.
- Make Ahead: The crust can be made a day in advance and refrigerated.
- Serving Suggestion: Serve with whipped cream or vanilla ice cream for extra indulgence.
Why You’ll Love It:
- Feeds a Crowd: Perfect for parties and potlucks.
- Sweet-Tart Balance: The raspberries and rhubarb create a vibrant, jammy filling.
- Rustic Charm: A slab pie is easier to assemble than a traditional round pie and just as beautiful.
- Versatile: Easily adaptable with different fruits or spices like cinnamon or ginger.
This Raspberry-Rhubarb Slab Pie is a celebration of seasonal fruit and buttery pastry, baked into a shareable sheet-pan dessert that’s as beautiful as it is delicious. Want a crumble-topped version or a gluten-free crust next? 🍓🥧