Place the pork mince in a bowl. Remove the skin from the chorizo and finely dice it. Finely chop the chives. Peel and finely dice the shallots and the garlic. Mix all the ingredients together thoroughly alongside the seasoning and make small burger shapes in accordance with the size of your burger buns.
Peel the onions and slice them as fine as possible.
Place the sunflower oil in a large saucepan, when it's hot add the onions and cook them until they are golden brown. Once the onions are golden brown, add the brown sugar and the seasoning. Once the sugar has melted and has begun to form a caramel, add the butter. Turn down the heat and cook for a further 10 minutes until the onions are soft.
When the onions are sticky and soft, remove from the heat and set aside ready for assembling the burgers.
In a small bowl, whisk together the mustard, and the vinegar. Slowly add the olive oil to form a vinaigrette. When the vinaigrette is made, mix it with the rocket.
Heat a large frying pan, when it is hot add the sunflower oil followed by the pork burgers. Cook for 3 minutes on each side.
When the burgers are cooked, place them into the burger buns. Top them with the onion relish and finish with the dressed rocket.
«Try to use uncooked chorizo for this recipe as cooked chorizo will be too tough.»