Shiitake Mushroom and Sweet Onion Burgers

• 3 tablespoons extra-virgin olive oil
• 2 tablespoons unsalted butter
• 1 large sweet onion, sliced
• 2 pounds shiitake mushroom caps, sliced
• Sea salt and fresh ground black pepper
• 3 pounds ground beef

1. Preheat grill to medium heat.
2. Heat a skillet over medium-high heat.
3. Add the olive oil and butter.
4. When melted, add the onion and cook until translucent, about 5 minutes.
5. Add the mushrooms, sea salt, and pepper, to taste.
6. Cook until the mushrooms are tender, about 5 minutes.
7. Remove the pan from the heat and allow to cool.
8. In a large bowl, combine the cooled onion mixture and ground beef with sea salt and pepper to taste.
9. To adjust seasonings, form a small test patty, cook, and taste.
10. Adjust if necessary.
11. Form the meat mixture into 6 patties.
12. Place the patties on the heated grill and cook, turning once, until desired doneness, about 2 to 3 minutes per side for medium-rare.

extravirgin olive oil, unsalted butter, sweet onion, shiitake mushroom caps, salt, ground beef

Taken from www.foodnetwork.com/recipes/shiitake-mushroom-and-sweet-onion-burgers-recipe.html (may not work)