Brown the Italian sausage in a pan over medium heat. Once cooked, add in the jar of spaghetti sauce and simmer until sauce is thick and cooked down. Roll out the prepared pie crust on a piece of parchment paper. Spoon some sauce onto half of the pie crust, top with your favorite pizza toppings. Fold the other half of the crust over the toppings. Seal the edges with a fork. Brush with egg wash. Bake at 375° for 30 to 40 minutes. Drizzle garlic butter over the finished calzone.