Mix flour ,garlic powder and cayenne pepper in a large bowl. Stir in cheese and parsley. Cut in butter until flour resembles coarse meal.
Make a well in the flour and pour in half and half. Stir until flour is wet and sticky. Turn out onto a generously floured surface. Sprinkle dough with enough flour to keep it from being sticky. Sprinkle flour on top and gently knead until dough is no longer stickly, adding flour as needed.
Roll out to one inch thick. Dip 2 ½ inch biscuit cutter into flour. Cut biscuits. Place 1 inch apart on a cookie sheet that has been sprayed with non-stick spray or covered with a baking mat. Brush tops with cooking oil.
Bake at 450 degrees in a preheated oven for 12 to 15 minutes or until tops are golden brown.