For the mayonnaise, wash the limes hot, dry them and finely grate the peel. Squeeze the limes. In a tall mixing bowl, mix half the lime zest, 2 tbsp lime juice, egg yolk, mustard and 1⁄4 tsp salt with the whisks of the mixer.
Stir in 100 ml oil, first drop by drop, then in a thin stream until the mayonnaise is thick and creamy. Season to taste with salt, cayenne pepper and paprika. Cover and put in a cool place.
For the chimichurri, peel the garlic. Wash the parsley, shake dry. Chop finely with the garlic. Mix with the rest of the lime zest, juice and 4 tbsp. oil. Season to taste with salt, chili flakes, oregano and thyme.
Set aside.
Onions peel, halve and cut into fine strips. Wash rosemary, dab dry, chop needles finely. Heat 2 tablespoons of oil in a frying pan. Caramelise the onions with 1 tbsp. sugar while turning for approx. 4 minutes.
Add rosemary at the end. Season with salt and let it cool down.
Sort the salad, wash and drain. Wash and slice the tomatoes. Place one slice of cheese on each half of each slice of ham. Fold other halves of ham over the cheese.
Cut the rolls in half horizontally, roast them in portions with the cut surfaces facing down in a hot pan without fat for about 2 minutes. Remove. Fry the bacon in the pan without fat until crispy. Remove from the pan and drain on kitchen paper.
Rinse meat cold, dab dry and season with salt. Fry in bacon fat for about 2 minutes, turn and season with gaucho pepper or another pepper mix. Place ham and cheese parcels on top and fry for approx. 2 minutes more.
Spread the undersides of the rolls with mayonnaise. Pile on lettuce, tomatoes, meat with ham packets, bacon and onions. Spread the tops of the buns with chimichurri and place on the burger.