Onion Relish

2 pounds large sweet onions, chopped
2 celery stalks, sliced
1 medium red bell pepper, chopped
1 tablespoon melted butter
3/4 cup apple cider vinegar
1/4 cup water
2 tablespoons brown sugar
1 teaspoon celery seed
1/4 teaspoon salt

Sauté onions, celery and red bell pepper in the butter in a Dutch oven for 15 minutes or until tender. Do not brown. Add the vinegar and remaining ingredients to the mixture.

Bring to a boil, reduce the heat and simmer, uncovered, for 20 minutes. Store in refrigerator. Serve chilled or at room temperature. Makes 1 quart.