Balsamic Onion Marmalade

Directions

1. 1
   Peel the onions. Cut in half through the root. Thinly slice into half-moon shapes.
2. 2
   Set electric skillet to 300°F Add oil and wait until it shimmers. Add a layer of onion and sprinkle with a little salt. Continue layering onion and salt until all the onions are in the pan. Cover and let stand, untouched, 20 minutes.
3. 3
   Sprinkle in black pepper to taste, then sugar. Cook, stirring often, 10 minutes, until onions look fairly dry.
4. 4
   Add vinegar and cook, covered, stirring occasionally, 1 hour, or until onions are very soft and a dark mahogany brown. Serve warm or at room temperature. It will keep, refrigerated, up to 1 month.