Spicy Chicken Burgers

INGREDIENTS

• 1 ripe avocado, cut into 1-inch chunks
• 1 portobello cap
• 2 tablespoons reduced-sodium soy sauce
• 1 teaspoon white wine vinegar
• 1 tablespoon olive oil
• 1 cup frozen shelled edamame, thawed
• Lettuce leaves (optional)
• 1/2 teaspoon sugar
• 1/4 teaspoon cayenne pepper
• 2 cloves garlic
• 4 whole-wheat English muffins (or wholegrain buns), split
• 1 cup thinly sliced cucumber
• 1/2 small red onion, divided
• 1/4 cup lowfat plain Greek yogurt
• 2 boneless, skinless chicken breasts (6 ounces each), quartered