Burger with caramelized onions and herb butter

Slice the onion into thin rings to unlock its natural sweetness. In a large skillet, heat the vegetable oil, let it shimmer, and add the onion. Salt and season with freshly ground black pepper to let the aromas unfold. Cook over medium heat, stirring occasionally, until the onion is translucent and soft, about 7–8 minutes. Reduce the heat to low, add the tomato paste and sweet and sour sauce, heat to combine the flavors, about 1 minute. Add the butter and brown sugar, pour in the apple cider vinegar and add a little hot water, 2–3 tablespoons will be enough. Continue cooking, stirring gently with a spatula, until the liquid has completely evaporated, about 10–12 minutes. The onion should become soft, stewed, and deliciously caramelized. Transfer it to a bowl and let it cool to reach its full flavor potential.

To make herb butter, create an aromatic base. Finely chop the onion, place it in a saucepan, add apple cider vinegar and heat over low heat, stirring, for 3–4 minutes. Transfer to a bowl and cool slightly so that the onion releases its aroma. Mash the onion thoroughly with a fork, then combine it with room temperature butter, salt, pepper and rub thoroughly so that all ingredients combine harmoniously. Add the finely chopped fresh herbs and mix gently.

Prepare perfect burger patties. Form 4 round patties from the ground meat, approximately 1.5 cm thick, so that they cook evenly. Preheat the grill, grease the grate with vegetable oil to prevent the patties from sticking. Place the patties on the grate, salt, pepper, and fry for about 3 minutes on each side. Flip to the other side, put a slice of cheese on each patty so that it begins to melt, and continue cooking for another 2 minutes. Transfer the patties to a plate and let them rest for a while, about 5 minutes, so that the juices are evenly distributed.

Assemble a culinary masterpiece – a burger. Cut the buns lengthwise in half, place them cut-side down on the grill rack and toast for about 30 seconds until they develop a crispy crust. Generously grease the buns with herb butter and place them on a plate. Place a fresh lettuce leaf and a juicy patty on the bottom halves of the buns, add caramelized onions, and cover with the top half of the bun.