* 3 Tablespoon butter
* 2 yellow onions, sliced
* 1 red onion, sliced
* 1/2 cup sweet marsala wine
* 1 Tablespoon balsamic vinegar
* 2 teaspoons honey
* 3 bay leaves
* 1/2 teaspoons dried thyme
* 1/2 teaspoons ground corriander
* 1/4 teaspoons ground allspice
* salt and pepper to taste

In a large skillet, melt the butter over medium heat. Add the sliced onions and cook until softened, but not browned.

In a small bowl, mix together the wine, vinegar and honey. Add to the onions. Add the bay leaves, thyme, corriander, allspice, and salt and pepper.

Bring the the mixture to a boil and then reduce to a simmer. Cook for 30 minutes, stirring occasionally. The wine should be reduced to a thickened syrup.

From: 

Accidental Hedonist - Onion Relish.