Prep: 7 minutes; Cook: 8 minutes
1. Heat a large nonstick skillet over medium-high heat. While skillet heats, combine first 4 ingredients in a large bowl; mix well. Divide mixture into 8 equal portions, shaping each into a 2-inch patty.
2. Coat pan with cooking spray. Add 4 patties to pan; cook 3 minutes. Carefully turn patties over; cook 1 minute or until lightly browned. Repeat procedure with remaining 4 patties. While patties cook, combine sour cream, lime juice, and chili powder in a small bowl.
3. Arrange cakes on a serving platter. Top each with sour cream mixture. Garnish with cilantro, if desired.