Lightly coat an 8" x 8" square casserole dish with cooking spray or butter then set aside. Add water and milk to a large saucepan then bring to a boil over medium-high heat. Once liquid is boiling, add polenta by gradually sprinkling it while constantly whisking to avoid lumps. Return mixture to a boil then remove from heat.

Stir in Parmesan cheese and butter until completely combined then immediately transfer to prepared dish. Spread evenly using a spatula or cover with a sheet of plastic wrap and press into an even layer. Work fast because the polenta will immediately begin to set. Cover with plastic wrap then refrigerate until cool, about 1 hour.

Preheat oven to 425 degrees, line a baking sheet with parchment paper and spray with cooking spray, preferably olive oil.

Remove polenta from refrigerator then turn out onto a cutting board. The polenta should come out easily in a solid mass. Cut in half into two 4" x 8" rectangles, then cut each rectangle into ¼" thick fries. You can make them any size you like, but the thinner they are the crispier they become.

Transfer fries to prepared baking sheet then bake 25-30 minutes, turning once halfway through cooking. Remove from oven then sprinkle with additional Parmesan cheese and a little more salt, pepper or garlic salt. Serve with marinara sauce or ketchup on the side for dipping.