- 1 pound ground beef
- A 1-ounce package of dried mushrooms (porcini, morels or other mushrooms)
- 2 teaspoons Worcestershire sauce
- 1/2 teaspoon kosher salt (add more if you like burgers a little saltier)
- 1/2 teaspoon freshly ground black pepper
- 1/2 pound fresh shiitake mushrooms (can substitute button or cremini), sliced
- 1 large onion, sliced thin (about 2 cups)
- 2 Tbsp olive oil
- 4-6 slices of Swiss cheese
- Burger buns
1 Process the dried mushrooms in a food processor, or a clean coffee grinder (grind some raw rice to clean out coffee grinds), until ground into a powder. Remove any large mushroom pieces that didn’t grind down, a few small pieces will be fine.
2 In a large bowl, use your clean hands to gently mix together the meat, salt, mushroom powder, black pepper and Worcestershire sauce. Mix just until everything is mostly combined, a minute or two. Do not overwork the meat mixture or it will become tough and meatloaf-like. Shape the meat into 3-4 patties, using about a quarter to a third of a pound per patty, creating a slight indentation at the centers of the patties (this will help keep the patties fairly flat when they cook, as the sides tend to contract more than the center).
3 Prepare your grill for high, direct heat. While the grill is heating up, heat a large sauté pan over high heat for 1 minute. Add the mushrooms and dry-sauté them until they release their water, about 2-3 minutes. Add the onions and the olive oil, toss to combine and continue to sauté over high heat 1 minute. Add salt to taste and cook until the onions soften and begin to brown. Turn off the heat and place in a bowl.
4 Grill the burgers to the desired doneness, between 5-8 minutes per side, depending on the thickness of the burgers and how hot your grill is.
5 When the burgers are almost done, lay the Swiss cheese over them and allow the cheese to melt. Paint the burger buns with a little olive oil and toast them on the griddle or grill grates. To assemble, put a burger on the bun and top with the sauteed onions and mushroom mixture.