I AM SO PROUD OF THIS BURGER. It was a major experiment and it worked! I truly believe that both carnivores and vegetarians will love this recipe. Mushrooms paired with Worcestershire sauce tend to create a meaty flavor, and the lentils pack this burger with protein. It's very crispy on the outside, and the inside is juicy, rich and delicious. Served on a whole wheat bun with arugula, Dijon mustard and melty Provolone cheese (which I put on top at the very end of the cooking process), it's perfect. PERFECT. I'M SHOUTING AT YOU AGAIN.
In a large skillet, heat 1 tablespoon of the olive oil over medium heat. Add the mushrooms, onion and garlic and sauté until tender and the onions are translucent, about 7 minutes. Stir in the Worcestershire sauce, remove from the heat and let cool briefly.
Transfer the mushroom mixture to a large bowl. Add the lentils, breadcrumbs, egg, salt and pepper to the bowl. Stir to combine.
Form into four patties and refrigerate for 30 minutes. When ready to cook, in a large skillet, heat the remaining olive oil over medium-high heat. Add the burger patties and cook until crispy, about 5 to 7 minutes. Add the cheese, cover and cook for 1 minute. Serve each patty on a whole wheat bun with arugula and Dijon mustard.