For a special treat my mother used to make herself a fried onion sandwich. Her grease of choice was bacon fat. From a kid standpoint it smelled pretty good but none of us were interested in trying any and she wasn't all that interested in sharing her special treat.
'nother story... my dad did a lot of special event catering. He did things like boat shows, garden shows... convention center type of stuff where he ran the concession. Around 11:00 in the morning he would put a huge pile of onions on the grill and then wink. By 11:15 we were selling lunch. There's just something about the smell of grilled onion that makes you want to eat.