Preheat oven to 400 degrees F. Mix the dry ingredients together. Cut softened butter in pieces and mix with the dry ingredients with a pastry blender or fork until crumbly.
In another bowl combine the liquid ingredients. Pour the liquids into the dry mixture and blend, but do not overmix. Grease muffin tins or line them with paper.
Fill two-thirds full or less with batter and bake 25 minutes for full-size muffins, 15 minutes for miniatures.