We've all had recipes that have called for "cold butter, diced". It's such a pain, in my opinion, to try to dice butter. Even when it's straight out of the refrigerator, it still starts melting pretty fast once your hand starts touching it.
I've discovered a tip that works for me!! I put the butter in the FREEZER about 20 minutes and then take it out and cut it into sticks and then dice it up. It's firmer so it cuts more easily and it doesn't melt as quickly when my hands touch it. After I dice it, I'll put it in a bowl in the refrigerator for a few minutes just to make sure it's cold when I use it. This way it's perfectly cold for my biscuits or pie crust or whatever I need "cold butter, diced" for!!!