Bbq Burger with Caramelized Onion

Ingredients

• 1 tbsp butter
• 1 onion, diced
• 1 garlic clove, minced
• 250 g (1 cup) ketchup
• 60 g (1/4 cup) brown sugar
• 40 ml (1/6 cup) Worcestershire sauce
• 25 ml (2 tbsp) white wine vinegar
• 1/4 tsp smoked paprika powder
• 1 tsp garlic powder
• 1 tsp dijon mustard
• 2 tbsp mayo
• 1 tsp olive oil
• 1 tsp butter, unsalted
• 2 onions
• 1sprig chopped rosemary
• 1 tsp honey
• 1 tsp white wine vinegar
• 400 g 2 beef patties (1/2 pound each) Z’Dežele
• 4 Cheddar cheese slices
• 2 burger buns
• 2 tomato slices