Turkish Beef Burger

Ingredients

• 1 pound Ground Beef (93% lean or leaner)
• 1/2 cup cooked couscous
• 1 egg
• 2 tablespoons finely chopped fresh mint leaves
• 2 teaspoons minced garlic
• 1 teaspoon grated lemon peel
• 1/2 teaspoon salt
• 1/2 cup Creamy Cucumber-Yogurt Sauce or prepared tzatziki sauce
• 4 whole-grain hamburger buns
• 2 cups romaine lettuce
• 4 slices red onion