Broccoli-Cauliflower Galette With Leeks and Ricotta Cheese

Preheat oven to 400 degrees F.
Heat the oil and butter in a medium pan over medium heat. Add the leeks, garlic, and thyme; season with salt and pepper. Cook, stirring occasionally, until golden brown and completely soft, about 10 minutes. Remove the leeks from the heat and allow to cool, while preparing the pastry dough.
Unfold the pastry sheet on a baking sheet. Using a sharp knife, score a line ½-inch inside the edge of the pastry sheet to form a border.
In a small bowl, combine the cooled leek mixture and the ricotta cheese. Smear the mixture onto the pastry dough, inside the scored borderline.
Top with broccoli and cauliflower leaving the same border.
Fold the edges of the pastry dough over toward the center, overlapping slightly and covering the filling by about 1 to 2 inches. Sprinkle the filling with mozzarella cheese.
Brush the pastry dough with egg wash. Bake in the preheated oven until golden brown; about 30 to 35 minutes.
For best results, use a pizza cutting wheel to cut the galette into slices. Serve warm.