Herby Porcini Beef Burgers with Oven-Roasted Cheddar and Caramelized Balsamic Onion

Prepare burger patties (at least an hour beforehand)

1.Prepare flavor base: Heat a little oil in a skillet over medium heat. Sauté the finely grated onion and minced garlic until soft and sweet, about 3-4 minutes. Allow to cool slightly.

2.In a large bowl, combine the beef mince, cooled sautéed onion and garlic, porcini mushroom powder, dried oregano, Worcestershire sauce, soy sauce, breadcrumbs, and egg yolk (if using). Season with salt and freshly ground black pepper.

3.Gently mix ingredients by hand until just combined, taking care not to overwork the meat to keep patties tender.

4.Shape the mixture into 4 patties approximately 1.5 cm thick. Place them on a tray and refrigerate for 30 minutes to help them hold together during cooking.

5.Preheat your grill or skillet to medium-high heat. Lightly brush the brioche buns with softened butter on the cut sides and toast them cut-side down until golden brown, about 1-2 minutes. Set aside.

6.Preheat the oven to 180°C (350°F). Line a baking tray with baking paper. Lay four slices of aged sharp cheddar cheese and sprinkle grated aged cheddar evenly on top of each slice. Roast in the oven for about 10 minutes until melted and starting to crisp. Let cool until firm enough to lift.

7.Caramelize onion: In a medium skillet over medium heat, melt 1 tablespoon of unsalted butter. Add thinly sliced onion and cook, stirring occasionally, until softened and golden, about 10-12 minutes. Add balsamic vinegar, stir well, and cook 2-3 more minutes until caramelized and slightly sticky. Remove from heat.

8.Grill patties on the preheated grill or skillet for 3-4 minutes per side without pressing down, to retain juices and ensure even cooking.

9.During the last 3-4 minutes of cooking, place the oven-roasted cheddar slices on top of each patty. Cover with a lid or loosely tent with foil to melt the cheese and finish cooking to desired doneness (medium recommended).

10.Remove patties from heat and let rest for 3 minutes.

11.Assemble the burgers: Spread mashed avocado on the bottom halves of toasted brioche buns. Place one large lettuce leaf and two thick tomato slices on each bottom bun. Add a generous layer of caramelized balsamic onion. Top with the rested beef patty crowned with oven-roasted aged cheddar cheese. Cover with the top half of the brioche bun and serve immediately.