Add sugar into softened butter, mash with fork then beat it with mixer.

Melt chocolate in microwave. I'd put it on high power and check every 10secs. Leave it to cool off (5minutes)

Add cocoa powder and pinch of salt, fold into the mixture. Alternatively add melted chocolate and milk. Beat until smooth

Extra tips: I always find myself making too much of cream with this recipe but not quite like the taste when I make half the recipe