Preheat your oven to 400°F (200°C).

Roll out your chilled puff pastry on a lightly floured surface to about 1/4 inch thick and fit into a tart pan. Prick the bottom with a fork and place in the refrigerator.

Heat 2 tablespoons of olive oil in a skillet over medium heat. Sauté the chopped onion and minced garlic until translucent (about 3-4 minutes). Add sliced cremini mushrooms and cook until golden brown; stir in fresh sage and thyme in the last minute.

In a mixing bowl, combine pumpkin puree, ricotta cheese, half of the grated Parmesan, and eggs. Season with salt and pepper, then fold in the sautéed mushroom mixture.

Pour the filling into the prepared pastry crust, smoothing the top. Sprinkle the remaining Parmesan on top. Bake for 30-35 minutes or until golden brown and slightly jiggly in the center.

Allow the tart to cool for about 10 minutes, then garnish with pumpkin seeds and fresh sage leaves before serving.