Mix the zest of the whole lemon, the juice of half a lemon, the finely chopped and pitted chillies and all the other ingredients with the butter. I always crush the garlic with a little salt and a fork. Season to taste with salt and pepper.
Note:
Instead of the chillies, I`ve also used red and green jalapeños. If necessary, the desired spiciness can be controlled by adding more chilli powder.