Raspberry-Rhubarb Slab Pie

This Raspberry-Rhubarb Slab Pie is a delightful twist on the classic pie, featuring a buttery crust filled with a sweet-tart combination of raspberries and rhubarb. Perfect for feeding a crowd, this slab pie is baked in a large sheet pan and topped with a simple vanilla icing for an extra touch of sweetness. It’s a show-stopping dessert that’s perfect for summer gatherings, potlucks, or family dinners.

Ingredients

For the Crust:

• 3¼ cups all-purpose flour
• 1 teaspoon salt
• 1 cup butter (cold, cut into small cubes)
• ¾ cup plus 1–2 tablespoons 2% milk

For the Filling:

• 1 large egg yolk (reserve the white for sealing the crust)
• 2 cups sugar
• ⅓ cup cornstarch
• 5 cups fresh or frozen unsweetened raspberries, thawed and drained
• 3 cups sliced fresh or frozen rhubarb, thawed and drained

For the Vanilla Icing:

• 1¼ cups confectioners’ sugar
• ½ teaspoon vanilla extract
• 5–6 teaspoons 2% milk

Instructions

Step 1: Prepare the Crust

1. In a large mixing bowl, whisk together the flour and salt. Add the cold cubed butter and use a pastry cutter or your fingers to work it into the flour until the mixture resembles coarse crumbs.
2. Gradually add ¾ cup of milk, stirring with a fork until the dough begins to come together. If the dough seems dry, add 1–2 additional tablespoons of milk as needed.
3. Divide the dough into two equal portions, shape each into a disc, wrap in plastic wrap, and refrigerate for at least 1 hour (or up to overnight).

Step 2: Make the Filling

1. In a large bowl, whisk together the sugar and cornstarch.
2. Add the drained raspberries and rhubarb to the bowl and gently toss to coat them evenly with the sugar mixture. Set aside while you roll out the dough.

Step 3: Assemble the Pie

1. Preheat your oven to 400°F (200°C). Lightly grease a 15×10-inch jelly roll pan or baking sheet.
2. On a lightly floured surface, roll out one disc of dough into a rectangle slightly larger than the size of your pan (about 17×12 inches). Carefully transfer the dough to the prepared pan, pressing it gently into the corners and edges.
3. Spread the raspberry-rhubarb filling evenly over the crust.
4. Roll out the second disc of dough to the same size as the first. Place it over the filling, trimming any excess dough. Use a fork or your fingers to crimp and seal the edges. Cut slits in the top crust to allow steam to escape during baking.
5. Beat the reserved egg yolk with 1 teaspoon of water and brush it lightly over the top crust for a golden finish.

Step 4: Bake

1. Bake the slab pie in the preheated oven for 40–45 minutes, or until the crust is golden brown and the filling is bubbling.
2. Remove from the oven and let it cool completely on a wire rack before icing.

Step 5: Make the Vanilla Icing

1. In a small bowl, whisk together the confectioners’ sugar, vanilla extract, and 5–6 teaspoons of milk until smooth. Adjust the milk as needed to achieve a drizzling consistency.
2. Drizzle the vanilla icing over the cooled pie, allowing it to drip slightly down the edges for a decorative finish.

Step 6: Serve and Enjoy

1. Slice the slab pie into squares and serve. Pair with a dollop of whipped cream or a scoop of vanilla ice cream for an extra indulgent treat.

Tips for Success

• Draining Fruit: Be sure to drain the raspberries and rhubarb well to prevent the filling from becoming too watery. Pat them dry with paper towels if necessary.
• Prevent Soggy Bottoms: For an extra layer of protection, sprinkle a tablespoon of crushed graham crackers or breadcrumbs on the bottom crust before adding the filling.
• Storage: Store leftovers in an airtight container at room temperature for up to 2 days or in the refrigerator for up to 5 days. Reheat slices in the oven for best results.
• Freezing: Wrap unbaked assembled pie tightly in plastic wrap and foil, then freeze for up to 3 months. Bake directly from frozen, adding 10–15 minutes to the cooking time.

Why You’ll Love This Recipe

This Raspberry-Rhubarb Slab Pie is a celebration of summer flavors, combining the tartness of rhubarb with the sweetness of raspberries in a buttery, flaky crust. The large format makes it perfect for sharing, while the vanilla icing adds a touch of elegance and sweetness. Whether you’re hosting a barbecue, potluck, or family dinner, this pie is sure to be the star of the dessert table. Dive into this sweet-tart delight and savor every bite!