1 (6-ounce) package sliced Portobella caps Salt 1/4 cup water Vegetable oil 1/2 large onion, thinly sliced 1/2 teaspoon dried oregano 4 slices American or mozzarella cheese 2 long sandwich buns (hoagie buns) 1/3 cup sliced peperoncini, cherry peppers or Read More …