Crusted Portabella Burgers Recipe – Sunset Magazine

Ingredients

• 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