Portobello mushrooms (which are overgrown cremini mushrooms) grow to a size that make them a perfect fit for a hamburger bun. Each cheese in the topping contributes something different: The fat-free mozzarella provides heft, and feta cheese provides intense flavor (which is why such a small amount is needed).
4 portobello mushrooms (4 ounces each), stems removed
3 tablespoons balsamic vinegar
1 tablespoon reduced-sodium soy sauce
6 ounces shredded fat-free mozzarella
2 tablespoons crumbled feta cheese (1 ounce)
4 whole-wheat rolls, split and toasted
3 cups mixed baby greens
1 Preheat the oven to 450°F. With a spoon or paring knife, scrape out the black gills from the underside of the mushrooms and discard.
2 In a shallow pan large enough to hold the mushrooms snugly in a single layer, stir together the vinegar and soy sauce. Add the mushroom caps and turn them over several times to coat them well with the vinegar mixture. Arrange the mushrooms stemmed-side up and let stand 5 minutes so that they absorb most of the liquid.
3 Bake the mushrooms, turning them over once, until tender, about 10 minutes. Turn the mushrooms stemmed-side up again and top with the mozzarella and feta cheese. Bake until the cheese has melted, about 3 minutes.
4 Top the toasted rolls with the greens and mushrooms. Makes 4 servings
good source of: calcium, fiber, selenium
Scraping the gills (the dark feathery undersides) off the portobello mushrooms keeps them from releasing as much liquid when they cook.
If you are concerned about sodium levels, be sure to read this before preparing this recipe: Sodium Intake and Salt in Recipes
From The Johns Hopkins Cookbook Library: Recipes for Weight Loss, edited by Lawrence J. Cheskin, M.D. and Lora Brown Wilder, Sc.D., M.S., R.D.