Hamburger with fries

INSTRUCTIONS

• 1
  First, peel the potatoes and cut them into fries. Place them in a large bowl, cover with water, and let them soak for 10 minutes to release starch. Then drain the water, cover the potatoes with fresh water again, and let them soak for another 10 minutes.
• 2
  Meanwhile, preheat the oven to 180 °C, prepare a baking sheet, and line it with baking paper.
• 3
  Drain the water, pat the fries dry, and spread them evenly on the baking sheet. Drizzle with oil, season with salt, and mix. Bake in the preheated oven for 30 minutes at 175–180 °C, then increase the temperature to 200 °C and bake for another 15–20 minutes until golden brown.
• 4
  While the fries are baking, roughly chop the onion and sauté it until golden brown over medium heat (4–5 minutes). Meanwhile, finely chop the pickled cucumber. Then, in a small bowl, mix ketchup, mustard, mayonnaise, sautéed onion, and chopped cucumber.
• 5
  After increasing the temperature for the fries, start preparing the meat, which should be at room temperature: Form it into 4 equally sized balls.
• 6
  In a large pan, melt butter over medium heat. Cut the buns in half, toast them in the pan until golden brown, cut-side down (1–2 minutes), and set aside.
• 7
  Clean the pan and heat oil over high heat. Place 2 meat balls in the pan and flatten them with a spatula into thinner patties, about 1 cm larger than the diameter of the bun. Season with salt and pepper and sear over high heat for 1–2 minutes. Flip, season again with salt and pepper, and sear for another 1–2 minutes. Then stack one patty on top of the other and remove from heat. Repeat the same with the remaining meat. After removing from the pan, let the meat rest for 4–5 minutes.
• 8
  Spread the prepared sauce on both halves of the toasted buns. On the bottom half, place tomato slices, then lettuce and the patty, and cover with the top half of the bun. Serve with fries.