In a large skillet over medium heat, cook the 6 slices of bacon until they are crisp and golden, about 5-7 minutes. Remove and drain on paper towels.

Using the same skillet with the bacon fat, add 4 sliced sweet onions, season with kosher salt and black pepper, and cook over medium-low heat for about 25-30 minutes until golden and soft. Pour in ½ cup of apple cider and cook for an additional 5 minutes.

Preheat your oven to 400°F (200°C). Roll out 2 sheets of thawed puff pastry on a floured surface, drape onto parchment-lined baking sheets, score a 1-inch border, and prick the center with a fork.

In a mixing bowl, combine 1½ cups of ricotta cheese and 1⅓ cups of pumpkin purée, seasoning with salt and pepper. Spread the mixture inside the pastry borders, top with caramelized onions, 2 cups of grated mozzarella, and the crisp bacon.

Sprinkle two handfuls of fresh sage leaves over the filling. Brush the edges of the puff pastry with a mixture of 2 eggs and 2 tsp of water. Bake for 25-30 minutes until the pastry is puffed and golden brown.

After baking, shower with grated Parmesan cheese and let rest for 10 minutes before slicing.