Combine wet ingredients in a second bowl and whisk well.
To bake, preheat oven to 400ºF. Grease muffin tins (or use muffin liners). Spoon desired amount of batter into pan. If desired, press fresh or frozen blueberries into muffins just before baking. Bake 18 minutes or until toothpick comes out clean. Cool 10 minutes. Serve warm.