Big Burger Sauce
1⁄4 cup mayonnaise
1⁄2 tbsp ketchup
1 tsp relish
4 portobello mushrooms
1 large zucchini
1 tbsp oil
8 lettuce leaves
8 slices whole wheat bread
- For the sauce, in a bowl combine mayonnaise with sauce mix, ketchup and relish. Set aside.
- Preheat grill to medium-high.
- Remove stems and scrape gills from mushrooms. Slice zucchini lengthwise into long strips. Brush each with oil and sprinkle evenly with seasoning. Thinly slice tomato and avocado; set aside.
- Place mushrooms and zucchini on grill. Grill, turning often until lightly charred and tender, about 8 min. Move pieces to a cutting board when done.
- To assemble sandwiches, coarsely chop mushrooms and zucchini. Spread bread with Big Burger Sauce; top 4 slices with lettuce, grilled veggies, tomato, and avocado. Cover with top pieces of bread. Cut in half and serve.