Balsamic Onion Marmalade

After a recipe from tom colicchio's _'wichcraft_, using a technique from alton brown.

Peel the onions.

Cut in half through the root.

Thinly slice into half-moon shapes.

Set electric skillet to 300f 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.

Sprinkle in black pepper to taste , then sugar.

Cook , stirring often , 10 minutes , until onions look fairly dry.

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.

onions, vegetable oil, kosher salt, fresh ground black pepper, sugar, balsamic vinegar