Raspberry Rhubarb Slab Pie
This raspberry rhubarb slab pie is a crowd-pleasing dessert with a flaky buttery crust, a vibrant sweet-tart fruit filling, and a simple vanilla icing drizzle. Perfect for potlucks, picnics, and spring gatherings, it serves up to 24 people with ease.
Servings: 24 pieces
Calories: 320kcal
Equipment
- mixing bowls
- pastry cutter or knives
- Rolling Pin
- 15x10-inch baking pan
- wire rack
Ingredients
- 3.25 cups all-purpose flour
- 1 tsp salt
- 1 cup cold unsalted butter, cubed
- 0.75 cup 2% milk
- 1 egg yolk
- 2 cups granulated sugar
- 0.33 cup cornstarch
- 5 cups raspberries (fresh or frozen, drained)
- 3 cups rhubarb, sliced (fresh or frozen, drained)
- 1.25 cups confectioners' sugar
- 0.5 tsp vanilla extract
- 5 tsp milk (for icing)
Instructions
- Whisk together flour and salt, then cut in cold butter until crumbly with pea-sized pieces.
- Whisk egg yolk with milk and gradually add to the flour mixture until dough just comes together.
- Divide dough into two portions (one larger), wrap, and refrigerate for at least 1 hour.
- Preheat oven to 375°F (190°C). Roll out the larger dough and fit into a 15x10-inch pan.
- Mix sugar and cornstarch, then toss with raspberries and rhubarb. Spread evenly over crust.
- Roll out remaining dough and place over filling. Seal edges and prick top with a fork.
- Bake for 45–55 minutes until golden brown and bubbling. Cool completely on a wire rack.
- Mix confectioners' sugar, vanilla, and milk to make icing. Drizzle over cooled pie, slice, and serve.
Notes
Keep the dough cold at all times for the flakiest crust. Drain frozen fruit thoroughly to avoid excess moisture. Allow the pie to cool completely before slicing for clean cuts. A light drizzle of icing is best—do not overdo it.