In a large bowl, combine flour, baking powder, salts and pepper. Stir in cheese, green onion, egg, mustard, milk, butter and crab, if desired. Combine wet mixture with flour mixture; stir until dry ingredients are moistened, don't over mix. Spoon into greased mini muffin cups. Bake at 350 degrees F for 20 minutes or until done. Cool on a baking rack.