Melt the butter. When it's cooled, pour it into a blender. Add all other ingredients and process until you get a smooth, creamy batter. If you have time, chill for about half an hour in the fridge.
Using a little butter, evenly grease a pancake pan or heavy-based frying pan.
Heat the pan, then pour a ladleful of batter in the middle, then tilt the pan to let the batter spread out evenly. Cook for about a minute, until the edge starts browning. Flip or turn it with a spatula and fry the other side for about 30 seconds.
Slide it onto a plate and repeat the cooking process with the remaining batter. You should get about 8 pancakes.