Preparation
- 1
Slice the tomato and cucumber into thin rounds.
- 2
Take half a red onion and slice it into fine rings. Set them aside for later. Finely chop the other half of the red onion for the caramelized onions.
- 3
Slice the zucchini into about 0.5 cm thick rounds and the bell pepper into bite-sized pieces.
- 4
Prepare the secret sauce: In a small bowl, mix equal parts ketchup and mayonnaise with a splash of lemon juice, a splash of soy sauce, and half a teaspoon of spicy mustard. Stir everything well.
- 5
Slice the burger buns into three parts each: a bottom bun, a middle piece, and a top bun.
- 6
Divide the ground beef into four equal balls. Optionally, mix it with some pepper, salt, and a few old breadcrumbs if you like the patties a bit softer.