Worst: Her "pot roast". I understand that it's a comfort food for many families but I never, ever got the point of pot roast. I want my carrots to taste like carrots, my potatoes to taste like potatoes and my meat not to absolutely fall apart before I can get it to my mouth.
Best: Her invention "shepherd's pie burgers". She'd cut hamburger with a can of tomato paste, fry the burgers till cooked. Cover each burger with a patty of stiff mashed potatoes and then (while still in the pan) throw a good large but thin slice of cheddar cheese over them. There was just something about the tomato paste that made them amazing, it caramelized and changed the flavor completely.