This look so great! I grew up with potatoes au gratin, sheperd's pie, chicken noodle casserole...although could never quite get my head around tuna, lol! :P BUT I need help! I make these for my friends and when they go to heat them through in the oven after being refrigerated, we can NEVER quite get the heating right. It's always cold in the middle or burnt on top...ick. Any tips?