Mix dry ingredients together in a large bowl, stirring them well to combine thoroughly. Toss the grated cheese with the flour mixture.
Melt butter, add milk, and stir. Add the egg and beat to combine. Add to the flour and cheese, and stir until just combined. You may find you need a bit more milk – it depends on the season and humidity.
Portion batter into prepared muffin cups, and bake 12 to 15 minutes, until the tops show some brown spots and a toothpick inserted into the center of one muffin comes out with no smears of uncooked batter.
Let cool in the tin for 10-15 minutes, then remove muffins and let them finish cooling on a rack. The muffins are splendid served warm – but just as good when cooled.
NOTE: Recipe may be doubled; baked muffins may be frozen.