This is the recipe I use in France, starting with a can of cassoulet beans.
1 large can white beans OR cassoulet (beans only)
2 strips of bacon
1/2 onion, chopped
1/4 cup ketchup
1 tsp yellow mustard
1 tsp sugar
4-6 dashes Worcestershire sauce
Cook the bacon in a frying pan until crisp. Set bacon asside and sauté the onions in the bacon grease.Once soft and slightly golden, Add beans, crumbled bacon and remaining ingredients. Simmer until hot. Taste and adjust seasonings as needed.