Nigella Express: Chocolate Pistachio Fudge

Taken off telly: (photo is my own)

Ingredients (Makes 64 squares)
350g good dark chocoloate
400g condensed milk (1 can)
2 tbsp butter
150g pistaschio

Method
1) Break the dark chocolate into a pan and pour the condensed milk on top.
2) Add the butter and turn on the stove.
3) Pour the pistaschio into a freezer bag and bash away into tiny chunks.
4) Stir to combine the fudge and then add the nuts, then stir again.
5) Pour into a tin foil tray, and spread out the mixture evenly.
6) When cool, put on the lid and place in the fridge to set.
7) Once it has set, remove from the tin foil tray and cut into cubes, approx an inch by an inch because it is quite rich.