Carmelized Onion and Ham Sandwich sliced ham country bread 2 medium onions, sliced 2 Tbs olive oil 2 Tbs sugar 1 Tbs red wine vinegar 1. Combine onions, olive oil, sugar, and vinegar in a frying pan. fry at medium high temperature until translucent and browned 2. Spoon onto bread slices 3. Briefly warm ham slices in the frying pan (no need to clean it out) and put slices over onions. 4. Put another slice of bread on top and serve.