A Juicy, Tangy, and Rustic Dessert That’s Perfect for Sharing!
This Raspberry-Rhubarb Slab Pie is a celebration of spring and summer flavors. The vibrant combination of sweet raspberries and tart rhubarb creates a luscious filling that's perfectly balanced, while the large slab format makes it easy to serve a crowd. With its flaky buttery crust and generous portion of fruit, this pie is as impressive as it is delicious.
Ingredients
For the Crust
- 3 cups all-purpose flour
- 1 tablespoon granulated sugar
- 1 teaspoon salt
- 1 cup (2 sticks) unsalted butter, cold and cubed
- ½ to ¾ cup ice water
For the Filling
- 4 cups sliced fresh rhubarb (about 1 lb)
- 2 cups fresh or frozen raspberries
- ¾ cup granulated sugar (adjust based on sweetness of fruit)
- ¼ cup light brown sugar
- 2 tablespoons cornstarch
- 1 teaspoon lemon juice
- ½ teaspoon ground cinnamon
- ¼ teaspoon salt
For the Egg Wash and Topping
- 1 large egg, beaten with 1 tablespoon water
- Coarse sugar (optional, for sprinkling on top)
Instructions
Step 1: Make the Pie Dough
- In a large mixing bowl, whisk together the flour, sugar, and salt.
- Add the cold cubed butter and use a pastry cutter or your fingers to work it into the flour mixture until it resembles coarse crumbs with some pea-sized pieces of butter remaining.
- Gradually add the ice water, one tablespoon at a time, mixing gently with a fork until the dough comes together. Be careful not to overwork it.
- Divide the dough in half, shape each half into a disk, wrap tightly in plastic wrap, and refrigerate for at least 1 hour (or up to 2 days).
Step 2: Prepare the Filling
- In a large mixing bowl, combine the sliced rhubarb, raspberries, granulated sugar, brown sugar, cornstarch, lemon juice, cinnamon, and salt. Stir gently to coat the fruit evenly.
- Let the filling sit for 15-20 minutes to allow the juices to release, then stir again.
Step 3: Assemble the Pie
- Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper for easier cleanup.
- On a lightly floured surface, roll out one piece of chilled dough into a rectangle about 1/8-inch thick. Transfer it to the prepared baking sheet.