Flying Dutchman burgers 🧅 Serves 2 Takes 20 mins 3 tbsp mayonnaise 1 tbsp tomato ketchup ½ tbsp American mustard 4 gherkin slices, finely chopped, plus 1 tsp gherkin liquor from the jar ½ tbsp olive oil 1 extra-large onion, cut into 4 thick circular slices, approx. 1.5cm 250g 15% fat beef mince, rolled into 4 equal-sized balls 4 mild cheese slices 1. Mix together the mayo, ketchup, mustard, gherkins and the gherkin liquor to make the burger sauce. Set aside. 3. Heat the oil in large frying pan over a medium-high heat. Fry the onion slices for 5 mins each side, until lightly charred and softened. Season with salt and pepper and set aside on a plate whilst you cook the burgers. 4. Add the beef mince balls to the pan. Place a piece of baking paper over each ball and use a potato masher or fish slice to push them down into thin patties. Season with salt and pepper and fry for about 2-3 mins, or until golden and crispy at the edges, then flip over. 6. Top the patties with the cheese sli...