A fruit and fiber packed knife and fork burger that's perfect atop a salad, or on a whole wheat bun.
Combine blueberries, mustard, vinegar, 1/2 teaspoon garlic and Worcestershire in food processor bowl. Pulse on and off until slightly chunky; reserve 1/2 cup of blueberry mixture for topping. Combine remaining blueberry mixture, ground beef, remaining 2 teaspoons garlic, flax, salt and pepper in medium bowl, mixing lightly but thoroughly. Lightly shape into four 1/2-inch thick patties.
Heat large nonstick skillet over medium heat until hot. Place patties in skillet; cook 10 to 12 minutes or until instant-read thermometer inserted horizontally into center registers 160°F, turning occasionally.
Serve burgers on a bed of mixed greens; top with reserved blueberry sauce and cheese.