Portabella "CheeseSteaks"

Preheat the oven to 350°F (175°C).

Place the mushrooms in a large saucepan and liberally sprinkle with salt. Add water, turn the heat to medium, and cover. After 6 minutes the mushrooms will have released most of their liquid. Salt again so the mushroom flavor is very strong, and remove and place the mushrooms on a paper towel-lined plate.

Heat about 2 tablespoons oil in medium skillet and add the onion. Fry the onion until very limp and browned, about 10 minutes. Turn down the heat to low, and season with a little salt and the oregano.

Form the onion into a rectangular shape to approximate the shape of the buns into which they will go. Cover with the cheese. Cover the saute pan until the cheese melts. Remove the cover and cut the onion-cheese mixture down the middle so you have 2 thin, narrow halves, making it easier to transfer the mixture onto the buns.

Cut the buns almost in half lengthwise, making sure the "hinge" stays intact. Place half the onion-cheese mixture onto each bun with a spatula and add half the mushrooms. Cover with any remaining sauce from skillet and finally top with the hot peppers, if desired.