In a saucepan, combine the ketchup, sugar, vinegar, and Worcestershire sauce. Stir in the seasonings and let the mixture simmer for about 20-25 minutes.
In a separate skillet, sear the ham until the edges turn slightly crispy. Be careful not to overcook, as the ham can dry out.
Pour the sauce over the ham and mix well. Serve on toasted buns, topped with a little yellow mustard.