Notes: We weren’t real fond of this. Too much mushroom for us. We might eat them again but not on a regular basis.
We served them with broiled Sweet Potato Fries.

Ingredients:
Portobello mushroom – 8 ounces
Tamari (low-sodium) – 2 ounces
Worcestershire sauce (vegetarian) – 2 ounces
Pepper, cracked – 2 ounces
Red onion (large) – 6 ounces
Whole grain bun – 2 bun
Hummus – 2 ounces

Directions:
Preheat oven to 450º.
Snap the stems off the mushrooms.
Place the mushrooms face-up on a baking sheet.
Splash a few drops of tamari and Worcestershire into each cap.
Cook in a casserole dish for 10–15 minutes, until the mushrooms are soft and filled with liquid.
Cook the onion rounds on high heat in a sprayed skillet for 5 minutes, stirring often, until wilted and brown.
Spread the buns with Dijon mustard or hummus.
Place each mushroom on a toasted bun with cooked onion, tomato, lettuce or spinach, and your favorite fixings.

Source: Unknown.