For the relish: Cook the peppers and onions in some olive oil in a skillet over medium heat until soft. Add the vinegar, sugar, dry mustard, cayenne pepper and garlic. Lower the heat and cook until all the ingredients are cooked down and thick enough to top the burgers, about 15 minutes.
For the burgers: Mix the beef, lamb, bell peppers, mint, onions, allspice, cloves, coriander, cumin, black pepper and cayenne pepper. Form into 4 patties.
Cook the burgers to your liking in a skillet or on a grill. Serve with the red pepper relish.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.