In a bowl, mix together all of the ingredients until just combined. Do not overmix. Divide the batter evenly in a 12-portion nonstick muffin tin. (If using a tin that isn't nonstick, spray with cooking spray).
Bake in the center of the oven until just golden and muffin springs back when gently pressed, about 20 minutes.
Cool for 10 minutes in the pan, then remove and serve warm.