Preheat an oven to 350 degrees F (175 degrees C). Grease a broiler pan or other pan with rack.
Mix together the baking mix, sausage, Cheddar cheese, Parmesan cheese, milk, and parsley. Shape the mix into 1-inch balls and place on the prepared pan.
Bake the sausage balls in the preheated oven until brown, about 25 minutes.