The Best Double Burger

Slice the tomato and cucumber into thin rounds.

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.

Slice the zucchini into about 0.5 cm thick rounds and the bell pepper into bite-sized pieces.

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.

Slice the burger buns into three parts each: a bottom bun, a middle piece, and a top bun.

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.

Put the chopped red onion with a little sugar in a pan and caramelize it over medium heat until it's nice and soft and lightly browned. Remove it from the pan and set it aside.

Heat some olive oil in a stainless steel pan. Roast the sliced zucchini and bell pepper in it until they are golden brown and slightly soft. Remove the grilled veggies from the pan and set them aside.

In a small pan over medium heat, briefly toast all cut sides of the burger buns.

Heat some oil in a large stainless steel pan over high heat. Place the prepared ground beef balls one by one into the pan and press them flat, either with a burger patty press or the oiled bottom of a pot.

Fry the patties on the first side until they are nicely browned and cooked about halfway through. Then flip them.

Immediately place two slices of Cheddar cheese on each flipped patty. Cover the pan with a bowl and let the cheese melt for about 30 seconds while the patty finishes cooking on the second side.

Once the patties are done and the cheese is melted, remove them from the pan and immediately start assembling the burgers.

Take the bottom bun of a burger bun and generously spread it with the secret sauce to make it nice and juicy.

Place one or two leaves of iceberg lettuce on the sauce.

Place the first patty with the melted Cheddar cheese on top.

Now add the crispy veggies: the fresh onion rings, tomato, and cucumber slices.

Take the middle piece of the burger bun, generously spread both sides with sauce, and place it on the crispy veggies.

Place the caramelized onions on the middle bun piece.

Place the second patty with the melted Cheddar cheese on the caramelized onions.

Spread the grilled veggies (bell pepper and zucchini) on the second patty.

Also generously spread the top bun of the burger bun with sauce. Drizzle one to two more tablespoons of sauce over the grilled veggies.

Place the top bun on the burger. For stability, stick a toothpick from top to bottom through the center of the entire burger.

Serve your awesome double burger immediately and enjoy it!