Prosciutto and Gruyère Quiche with Bacon and Mushrooms (Puff Pastry)

Passed along to me from an extraordinary cook and caterer, so I knew before the savoury puff-pastry quiche even crossed my lips it would be divine. It is also very simple which is a bonus.

2 sheets frozen puff pastry, thawed (one 17.3 oz pkg)
6 slices thick cut peppered bacon, cooked and chopped
6 slices prosciutto, chopped
2 cups Swiss cheese, such as Gruyère, coarsely grated
2 cups mushrooms, sliced
2 large eggs
1 Tbsp. fresh rosemary, chopped
½ tsp. black pepper, freshly ground
½ tsp. sea salt
¼ tsp. ground nutmeg
1 cup sour cream

Preheat oven to 400°F (200°C/180°C fan, Gas Mark 6).

Sauté mushrooms until just barely done. Drain liquid. Unfold both pastry sheets on two separate baking pans. Top each pastry evenly with bacon, prosciutto, cheese and mushrooms, leaving ½" border. Whisk eggs, sour cream, rosemary, pepper and salt in a bowl.

Spoon egg mixture over toppings on each pastry. Bake until pastries are puffed and golden and toppings are set, about 25 minutes.