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“Best raspberry rhubarb slab pie recipe with flaky crust and fruity filling.”

Best Raspberry-Rhubarb Slab Pie Recipe

Summary: This best raspberry-rhubarb slab pie recipe features a flaky, buttery crust filled with tart rhubarb and sweet raspberries for a fruity, crowd-pleasing dessert. Perfect for family gatherings, summer picnics, or an easy weekend baking project.
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Ingredients Equipment Method Notes

Ingredients
  

  • Ingredients:
  • For the Crust:
  • 2 ½ cups all-purpose flour
  • 1 tsp salt
  • 1 tsp granulated sugar
  • 1 cup 2 sticks unsalted butter, cold and cubed
  • 6 –8 tbsp ice water
  • For the Filling:
  • 3 cups rhubarb chopped
  • 2 cups fresh raspberries
  • 1 cup granulated sugar
  • ¼ cup cornstarch
  • 1 tbsp lemon juice
  • 1 tsp vanilla extract
  • For Assembly:
  • 1 egg for egg wash
  • 1 tbsp coarse sugar optional

Equipment

  • Equipment:
  • Mixing bowls
  • Pastry cutter
  • Rolling Pin
  • 9×13-inch baking pan
  • Pastry brush
  • Knife
  • - Measuring cups and spoons

Method
 

  1. Instructions:
  2. 1️⃣ In a large bowl, whisk together flour, salt, and sugar. Cut in the cold butter using a pastry cutter or fingers until coarse crumbs form.
  3. 2️⃣ Add ice water gradually, one tablespoon at a time, until the dough comes together. Divide into two disks, wrap in plastic wrap, and chill for 1 hour.
  4. 3️⃣ Preheat oven to 375°F (190°C). Lightly grease a 9x13-inch baking pan.
  5. 4️⃣ In a separate bowl, gently mix rhubarb, raspberries, sugar, cornstarch, lemon juice, and vanilla extract.
  6. 5️⃣ On a floured surface, roll out one dough disk into a rectangle slightly larger than your pan. Fit into the pan, letting the edges hang over.
  7. 6️⃣ Pour the fruit mixture evenly into the pan.
  8. 7️⃣ Roll out the second disk and either cover fully or cut into strips to create a lattice. Trim excess dough and crimp the edges.
  9. 8️⃣ Beat the egg and brush over the top crust. Sprinkle with coarse sugar if desired.
  10. 9️⃣ Bake for 45–50 minutes or until the crust is golden and the filling is bubbling. Let it cool completely before slicing into squares.

Notes

Notes:
For a warmer flavor, add a pinch of cinnamon or cardamom to the filling.
Use frozen rhubarb if fresh is unavailable (no need to thaw).
Serve with vanilla ice cream or whipped cream for a delicious finish.
Let the pie cool completely before slicing to help it set cleanly.