Preheat the oven to 400 degrees F. Line 2 baking sheets with parchment paper.
Roll a pie crust to 1/4- to 3/8-inch thick, dusting with flour as necessary, and shaping it as close to a rectangle as possible. Cut long strips of crust about 1/2 inch wide with a fluted pastry wheel. Trim the strips to about 4 inches long. Carefully transfer the strips to the lined baking sheet. Coat with egg wash. Sprinkle the "fries" with half the Parmesan. Repeat with the remaining pie crust.
Bake until lightly golden brown, 12 to 15 minutes. Let cool slightly on the baking sheets. Garnish with the parsley and serve with the marinara sauce.