Whiz the egg, milk, tartar sauce, baking powder in a blender. Add gradually the gram flour until you get double cream consistency. Add the spinach, cayenne and a small spoonful of olive oil. Whizz for a few second until smooth.
Now add the crayfish tails and whizz for a few seconds until you get a textured batter. If you have time, rest for 10 minutes.
Oil and heat a pancake pan or heavy based frying pan over medium heat.
Add dollops of the batter, allowing them to spread out into circular shapes.
When they are cooked through (i.e the top surface is no longer runny), flip them over and cook for another minute or so.
Transfer them to a plate and make more pancakes, finishing off the batter.
Serve warm or at room temperature.