Here's one I've made a couple times, only that was a restaurant yield that gave about a gallon and a half of marmalade. I'll warn you now, your kitchen and house will smell like vinegar for awhile. This is a very interesting condiment for sandwiches.
Red Onion Marmalade
2 large red onions, thickly sliced
1 T butter
1 t garlic, minced
cider vinegar to cover
¼ c sugar
red pepper flakes, to taste
salt, to taste
In a small saucepan with a tight-fitting lid, sweat the onions in butter, with the lid on, until they collapse. Add remaining ingredients except sugar and reduce to au sec (almost dry). Add sugar and simmer, stirring constantly until sugar dissolves.
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