Blueberries add intense flavor and color to a dressing for grilled balsamic-marinated skirt steak. Serve over salad greens with feta cheese and red onion.
Place 3/4 cup of the blueberries, 2 tablespoons of the marinade, sugar, water and lemon juice in food processor. Cover. Process until smooth. Refrigerate dressing until ready to serve.
Place steak in large resealable plastic bag or glass dish. Add 1/4 cup of the remaining marinade; turn to coat well. Refrigerate 30 minutes or longer for extra flavor. Remove steak from marinade. Discard any remaining marinade.
Grill steak over medium-high heat 6 to 8 minutes per side or until desired doneness, brushing with remaining 2 tablespoons marinade. Cut steak into thin slices.
Divide salad greens evenly among 4 serving plates. Top each with steak slices. Sprinkle with remaining 3/4 cup blueberries, feta and onion. Serve with dressing.