Preparation time: 20 minutes & cooking time. Difficulty: 2/5. For servings: 2.
Make up the sauce in advance:
Peel and finely chop one onion and the garlic clove. Warm the olive oil in a pan and gently sweat the onion and garlic until soft and translucent, then add the rest of the ingredients and leave to cook over a gentle heat for 1 hour, stirring occasionally.
Leave to cool (you can keep the mixture in a bottle in the fridge).
Once the sauce is cold, finely chop the 2nd onion and add half of it to the mince, season with salt and black pepper and shape into burgers.
Cook the burgers for 2 minutes on each side.
Next assemble the burger as follows: bread, salad, cheese, meat, sauce, chopped onion, bread and serve accompanied with chips or potatoes and salad.