On a lightly floured surface, unroll the pastry. Transfer the crust into a pie pan (8-9 inches wide and 2 inch deep). Trim pastry off the edges of the pie pan.
Cover the pie crust with parchment paper. Fill it with rice or peas to hold the pie crust down. Bake at 350 °F for 30 minutes. Remove the pie crust from the oven, let it cool down and remove the rice from the crust.
Fill crust with mushrooms, bacon and sprinkle with mozzarella.
Whisk eggs together with heavy cream, pour over filled pie crust.
Bake at 375 °F for about 30 minutes or until a knife inserted near the center comes out clean.