Step 1

Preheat an oven to 400 degrees F (200 degrees C). Bake pie shells in the preheated oven until edge of crust is golden, about 10 minutes. Set crust aside, and lower the heat to 350 degrees F (175 degrees C).

Step 2

Heat a large skillet over medium-high heat, and stir in the sausage. Cook and stir until the sausage is crumbly, evenly browned, and no longer pink. Place the sausage on a towel lined plat,e and discard any excess grease from the pan. Add the mushrooms and butter to the skillet, and cook and stir until the mushrooms are a light golden brown, about 5 minutes. Spread sausage and mushrooms evenly over the bottom of pie crusts.

Step 3

Combine the cream, eggs, flour, butter, lemon juice, salt, and pepper in a medium bowl. Pour into the pastry crust, allowing egg mixture to thoroughly cover the sausage mixture. Sprinkle top with Parmesan cheese.

Step 4

Bake until light and puffy, about 35 minutes. Allow to stand 10 minutes before slicing.