The names are used loosely anymore to evoke that sense of the extraordinary in the really ordinary.
Here is and 'onion marmalade' I use from Helen Witty. It's not technically a marmalade either. My comments are in parentheses.
2 pounds paper thin sliced onions
3 tablespoons olive oil (If I knew I'd use it all in a week, I'd
use butter instead, but for keeping purposes olive oil is
4 large cloves garlic, minced
1/4-1/3 cup sherry vinegar (balsamic could be interesting too,
maybe thinned with some rice vinegar)
3 tablespoons honey or 2 tablespoons packed brown sugar.
2 teaspoons well crushed dried rosemary
1/2 teaspoon salt or to taste
pinch of cayenne
water (though an unsalted neutral stock would be fun to try)
Stir together the onions and olive oil in a nonreactice heavy
wide skillet. Cook, stirring often over medium heat until well
wilted and lightly colord. Pale gold, no more.
Stir in garlic, 1/4 cup of vinegar, honey, rosemary. Cook over
low heat stirring often until the mixture has ddepened in color
and is almost dry. Add enough water to reach to top of hte
onions. Cover partially. Cook over low with occasional stirring
until alsmot dry again. Test onions. Should hbae just a ghost of
a crunch. If crunchier, add more water and cool some more. Cook
until marmalade is light caramel in color and jamlike in texture
(using balsamic ruins the color test).
Remove from heat, cool. Season with salt, cayenne and more
vinegar as needed or honey or rosemary. Cap and store
refrigerated. Wil keep for a few weeks. Frozen, will keep for 2
months. Serve at room temp.