Pittsburgh Ham Barbecues

½ cup butter

1 small onion, finely chopped

2 cups ketchup

⅓ cup distilled white vinegar

½ cup water

3 tablespoons brown sugar

2 teaspoons prepared yellow mustard

2 tablespoons Worcestershire sauce

1 ½ pounds chipped chopped ham

8 kaiser rolls, split

1 cup pickle relish

Preheat an oven to 275 degrees F (135 degrees C).

Melt the butter in a large skillet over medium-high heat; cook and stir the onions in the butter until translucent, about 5 minutes. Stir the ketchup, vinegar, water, brown sugar, mustard, and Worcestershire sauce into the skillet with the onions; simmer about 10 minutes. Stir in the ham; cook until heated through and the sauce is bubbling, 5 to 7 minutes more.

While the ham simmers, heat the kaiser rolls in the preheated oven until toasted, 5 to 7 minutes.

Assemble the sandwiches by dividing the ham mixture among the toasted kaiser rolls, topping the ham with pickle relish. Serve hot.