In a food processor, whiz the salted peanuts until the texture is ground but rough. Then add the butter, flour, vanilla, egg, and sugar. Blitz a couple of times until mixed. Then gradually add the water until a dough forms. You may not need the entire 2 tablespoons. Wrap the dough in cling film and chill for 30 - 60 mins. Then spread in a 9” tart pan and bake for 22 minutes or until golden in a preheated oven at 180 degrees C.