Wow, these were delicious and there is no recipe. I basically took 4 portabellos, rinsed and patted them dry, de-stemmed them and sprinkled on some vegan steak sauce. Then, I threw the mushrooms gill side up in a 450 degree oven for 10 minutes. I took the stems, a half of an onion, and a chopped bell pepper and threw them in a pan. I sauteed with some water and towards the end I threw in a dash or two of steak sauce. I assembled the burgers gill side up so they could hold all the extra veggies. These were so, so, good!!!! My tummy is so happy tonight!
My eldest daughter doesn't like mushrooms so I served her the "ground" mushroom burgers by Happy Herbivore we made a while back and had thrown in the freezer. I just heated those up for her. She has no idea that the burgers are made of mushrooms and she devoured it.
I served these with some asparagus and roasted potatoes.