Preheat oven to 425 degrees. Spray mini-muffin tins with non-stick cooking oil. Place the flour in a bowl and cut in the butter. Stir in the Cheddar cheese and add enough milk to make a sticky dough. At this time, the dough may be refrigerated, covered. Bring to room temperature. Spoon dough into tins. Bake in the middle of the oven 10 to 15 minutes, until pale golden brown. Remove the muffins from tins and cool on a rack. The muffins may be frozen in a plastic bag