Blend the batter
Put all ingredients (except melted butter) into a blender and blend until smooth. Add the melted butter and blend for another 15-30 seconds. Thin out with additional milk if needed.
Heat the skillet
Warm a large, nonstick skillet over medium heat and coat lightly with butter or oil. Pour in desired amount of crepe batter and tilt the pan to spread it out thinly and evenly.
Let the first side cook for 1-2 minutes, until the sheen on top starts to set. Use a large, slender spatula to carefully flip and cook the second side for another 1 minute or so, until lightly browned in spots. Transfer to a plate and serve warm.