Crusted Portabella Burgers

• 2 large egg whites
• 1 tablespoon olive oil
• 1/3 cup Italian-style fine dried bread crumbs
• 2 tablespoons chili powder
• 4 portabella mushroom caps (5 in. wide; 1 to 1 1/4 lb. total)
• 4 round sandwich buns (4 in. wide; 3/4 lb. total)
• 1 cup nonfat sour cream
• 2 teaspoons minced canned chipotle chilies or hot sauce
• 1/4 cup thinly sliced red onion
• 1 cup spinach leaves, rinsed and crisped
• Salt
• Pepper

1. In a bowl, beat egg whites and oil to blend. In another bowl, mix crumbs and chili powder.
2. Rinse mushroom caps; drain. Coat each cap with egg mixture, drain briefly, then coat with crumbs, shaking off excess. Set caps, gill sides down, slightly apart on a 12- by 15-inch baking sheet. Lay bun halves, cut sides up, side by side on another 12- by 15-inch baking sheet.
3. Bake mushroom caps in a 450u0b0 oven until browned and flexible when pressed, about 20 minutes. About 3 minutes before mushrooms are done, add buns to oven; bake until lightly toasted.
4. In a small bowl, mix sour cream and chipotle chilies. Spread mixture on cut sides of buns. Layer equal amounts of onion and spinach on each bun bottom, top with a mushroom cap, add salt and pepper to taste, and cover with bun top.

egg whites, olive oil, italianstyle, chili powder, portabella mushroom caps, buns, nonfat sour cream, chilies, red onion, spinach leaves, salt, pepper

Taken from www.myrecipes.com/recipe/crusted-portabella-burgers (may not work)