2 or 4toasted burger bunsdepending on if you want double cheeseburgers
Toppings: sliced tomatoes, lettuce, sliced red onions
Prep Mushrooms: Clean portobellos gently with a damp paper towel. Remove stems (and gills, if you don't like the texture). In a small bowl, combine olive oil, soy sauce, lemon juice, garlic, and seasonings. Brush liberally onto the tops and bottoms of the mushrooms.
Cook Mushroom Burgers: Heat a large non-stick skillet over medium/high. Add the mushrooms and cook for 3 minutes on each side, or until slightly softened, brushing with remaining marinade to add more flavor. Alternatively, cook on the grill for 5 minutes per side until grill lines appear. Add cheese in the last minute of cooking.
Assemble & Serve: Combine all “Fancy Sauce” ingredients in a small bowl. Serve mushroom burgers on toasted buns with fancy sauce, tomatoes, lettuce, and onion.
Can you eat the gills of a Portobello mushroom? Yes! The texture can turn a little mushy during cooking, so you can scrape them out if you prefer your Portobello Mushroom Burgers without (but I like them with gills and all).