Outstanding combination of flavors! Meatless Monday might be Mushroom Monday every week from now on. I used plain Greek yogurt instead of mayo and it was a very tasty sauce - would also make a good creamy salad dressing.
Yum!! Super tasty. Forgot to butter the buns and saved a few calories. These are really quick to prepared and so flavorful. Thanks for posting this delicious recipe.
Way better than any meat burger I've ever had! I think all the flavors come together nicely in this, but I think the "secret" ingredient is the method of grilling the portabellos - it gives them such a great taste. We also opted to grill one red pepper (for 2 burgers) instead of using jarred, and I would highly recommend that. I added less mustard for my taste. These made a delicious meal!