1. Combine the batter ingredients in a blender and mix until smooth (20-30 seconds). Leave the batter for 10 minutes to allow the flour to absorb the liquid.
2. Mix again for 2-3 seconds.
3. Heat a dry heavy bottomed non-stick pan until very hot, add a little butter (ideally use an oil brush to spread around the pan).
4. Pour about 1/6 of the batter into the pan, it will start to set immediately. If you are brave enough flip the pancake when sufficiently set to cook on the other side, but otherwise turn with a spatula.
5. Keep the pancake warm on a plate in a warm oven. Make the next pancakes and pile up on the plate. When all of them are cooked roll them round the filling of your choice and serve.