Since we were going to be eating this at the end of a very busy day, I pre-made most of the ingredients the night before. I cooked the brownies, made the pudding and the peanut butter layers in advance. I just kept the pudding and peanut butter in the refrigerator. I took the peanut butter mixture out of the fridge about 15 minutes before assembling so it could warm up a bit. I added about 2 TBS of additional milk and whipped it for a minute or two before layering it.