Apple-Raspberry Slab Pie

Preheat oven to 375 degrees. On a lightly floured surface, roll out one piece of pate brisee to a 15-by-12-inch rectangle. Fit into a 13-by-9 1/4-inch rimmed baking sheet, pressing into corners. Trim to a 1-inch overhang all around. Chill while assembling filling.

Using a sharp knife, split vanilla bean and scrape seeds into a large bowl along with 1/4 cup flour, sugar, salt, cinnamon, apples, and lemon juice; toss to combine. Pour mixture evenly over chilled pie crust. Top with raspberries and dot with butter.

On a lightly floured work surface, roll out remaining piece of dough to a 15-by-12-inch rectangle; drape over filling. Fold edge of bottom dough over top dough. Pinch edges to seal. Using a sharp knife, make slits in the dough to create a star shape, to allow steam to escape. Chill for 20 minutes.

In a small bowl, whisk together egg and heavy cream. Brush top of crust with egg mixture and sprinkle with sanding sugar. Transfer to oven and bake until crust is deep brown, 65 to 75 minutes. Let cool slightly before cutting and serving.