Grilled Beef and Mushroom Burger

Ingredients

• 1 pound ground beef
• A 1-ounce package of dried mushrooms
• 2 teaspoons Worcestershire sauce
• 1/2 teaspoon kosher salt
• 1/2 teaspoon freshly ground black pepper
• 1/2 pound fresh shiitake mushrooms, sliced
• 1 large onion, sliced thin
• 2 tablespoons extra virgin olive oil
• Salt
• 4-6 slices of Swiss cheese
• Burger buns

Directions

1. Grind the dried mushrooms in a food processor or a clean coffee grinder until they become a fine powder. If the grinder needs clearing of coffee residue first, run some raw rice through it. Pick out any stubborn large bits of mushroom that refuse to break down; a few little flecks are completely fine.
2. In a large bowl, combine the ground beef, salt, mushroom powder, black pepper and Worcestershire sauce with clean hands. Be gentle and stop once the mixture is mostly blended, after a minute or two. If you handle it too much, the burgers can turn dense and meatloaf-ish.
3. Shape the beef into 3-4 patties, using about a quarter to a third of a pound for each one. Press a shallow dip into the middle of each patty so they cook up flatter instead of doming in the center.
4. Set up the grill for high, direct heat. As it warms, place a large sauté pan over high heat for 1 minute. Add the mushrooms to the dry pan and cook them until they give off their moisture, about 2-3 minutes.
5. Add the onions and olive oil, toss everything together, and cook over high heat for 1 minute more. Season with salt to taste, then continue cooking until the onions are tender and starting to color. Take the pan off the heat and transfer the mixture to a bowl.
6. Cook the burgers over high, direct heat until they reach your preferred doneness, about 5-8 minutes per side, depending on patty thickness and the strength of your grill.
7. When the burgers are nearly finished, place the Swiss cheese on top and let it melt.
8. Brush the burger buns lightly with olive oil, then toast them on a griddle or on the grill grates.
9. Build each burger by placing a patty on a bun, then spooning the sautéed onion and mushroom mixture over the top.