1: Put 200 g butter cut into small pieces in the bowl of the mixer and 200 g pistachio powder or paste, and knead briefly on low speed to soften.
2: Add 2 eggs and knead again on medium speed for 5 minutes. Add 1 tablespoon cornflour and 1 tablespoon rum, then continue mixing for a further 5 minutes.
This cream will keep for a few days in the fridge in a sealed container, but it also freezes well. You can then take out of the freezer just the quantity you need for your recipe.