1. Clean all vegetables, remove stems and gills from portobello mushrooms.
2. Place cleaned portobello mushrooms and 1/4 cup greek dressing in 2 large ziplock bags. Be careful not to crush the mushrooms.
3. Core peppers, and peel onions. Slice onions into 1/2 “ thick rings, and peppers keep as large as possible. Spray with high smoke point oil using a stainless steel spritzer, and season with pepper, oregano and a touch of salt.
4. Grill all vegetables on a stainless steel grill topper, or directly on the grill for harsher grill marks.
5. Remove cooked vegetables from the grill and reserve. Peel skins off peppers, separate onion into individual rings, use a pair of precision tongs, as the vegetables will be hot.
6. Place marinated mushrooms on a medium high preheated grill.
7. Grill 4 minutes each side, 2 minutes per turn @ 450° F
8. While the mushrooms are cooking, thinly slice the peppers and crumble your feta cheese.
9. Assemble the burger - using a stainless steel roasting pan, place the mushroom cap on the bottom, the peppers and onions on top and feta cheese to garnish.
10. Place back on grill under rotisserie burner for 3-5 minutes turning halfway through.
11. Assemble burger:
Grilled bun, greek mayo, sliced cucumber, sliced tomato, grilled mushroom cap with toppings, close the top bun.
12. Enjoy!