Any kind of pasta... Mac and cheese, spaghetti, tortellini, tuna or chicken casserole! I also enjoy buttered and garlic angel hair pasta with bacon bits in it. I find potatoes to be comforting too, be they mashed, boiled, baked or fried.
Bananas... For some reason, eating bananas helps brighten my mood. I just love them. Adding them to my PB&J even qualifies.
Sweets as well, of course. I won't go in depth with that one since there are so many that are good at comforting me. xD