• 4 tablespoons olive oil, divided
• 3 (8 ounce) packages sliced fresh mushrooms
• ½ medium onion, finely chopped
• 4 cloves garlic, minced
• 1 teaspoon salt
• ½ teaspoon black pepper
• ½ teaspoon dried oregano
• ¾ cup dry bread crumbs
• ⅔ cup rolled oats
• ½ cup freshly shredded Parmigiano-Reggiano cheese
• 2 large eggs, beaten

Directions

1. Heat 2 tablespoons oil in a large skillet over medium heat. Add mushrooms, onion, garlic, salt, pepper, and oregano; cook and stir until mushrooms have released their juices and the liquid has evaporated, about 10 minutes. Remove from the heat.
2. Transfer mushrooms to a cutting board and clean the skillet.
3. Chop mushrooms into small chunks, then transfer to a large bowl. Mix in bread crumbs and oats, and season with salt and pepper as needed. Stir in Parmigiano-Reggiano cheese, then eggs; let stand until bread crumbs have absorbed any excess liquid, about 15 minutes. Use moist hands to form mixture, 1/4 cup at a time, into patties.
4. Heat remaining 2 tablespoons oil in the skillet over medium heat. Pan-fry patties in the hot skillet until golden brown and cooked through, 2 1/2 to 3 minutes per side.