Preheat oven to 425 degrees.
Wipe caps and remove stems, some also remove the “gills” (dark brown underside of the cap) this is optional. Rub them with a bit of olive oil and season with salt and pepper. Arrange on a baking sheet and roast for 10-12 minutes.
Meanwhile, butterfly the chicken breasts so that there are 4 smaller fillets.
Blend olive oil, oregano, thyme, garlic powder, lemon juice, salt and pepper.
Brush seasoning onto chicken and place either on a BBQ, indoor grill, or sauté pan and cook for 2-3 minutes per side, make sure to use a digital thermometer and check the internal temperature is 165F.
In another sauté pan and a bit of olive oil, saute onions and peppers on medium heat or until onions are translucent.
Now you’re ready to build some burgers! Layer a portabella cap, chicken, goat cheese, onion and red pepper mix, and another portabella cap. The burger will be so juicy you don’t even need sauce!