Roll out 1 roll of pie dough into a 9 inch pie dish. Poke the pie crust several times with a fork. Bake at 350 degrees Fahrenheit for 10 minutes.
In a skillet, bring olive oil to medium high heat. Sauté the onion and garlic for about 4 minutes
Add the sliced mushrooms and diced carrots. Sauté for 3 minutes.
Add the turkey, green peas, corn, salt, black pepper, and dried thyme. Stir to combine.
Pour in the heavy cream, chicken stock, and shredded parmesan cheese. Cook for an additional 3 minutes.
Fill the baked pie crust with the turkey filling. Using a piping bag and tip of your choice, pipe out tiny mounds of mashed potatoes until the turkey filling is covered. Bake at 365 for 30 minutes or until bubbly. Depending on your oven, it may take more time.