| Ingredient | Amount | Type |
|---|---|---|
| Ground Beef (80/20 blend) | 600 | gram |
| Soy sauce | 1 | tablespoon |
| Worcestershire sauce | 1 | tablespoon |
| Garlic powder | 1 | teaspoon |
| Onion powder | 1 | teaspoon |
| Shiitake mushrooms | 150 | gram |
| Butter | 2 | tablespoon |
| Caramelized onions | 200 | gram |
In a skillet, sauté chopped shiitake mushrooms in butter until golden and reduced, intensifying their umami flavor. Set aside. Mix ground beef with soy sauce, Worcestershire sauce, garlic powder, onion powder, salt, and pepper. Form into 4 patties. Grill or pan-sear patties over medium-high heat until cooked to desired doneness. Top each patty with sautéed shiitake mushrooms and a slice of sharp cheddar cheese. Cover briefly so cheese melts. Toast brioche buns lightly for added flavor and structure. Spread truffle aioli on the bottom bun, then layer arugula, the umami-packed patty with mushrooms and cheese, caramelized onions, and pickled red onions. Crown with the top bun and serve hot.