1Preheat oven to 350^. Line 24 muffin pan cups with paper liners, or spray with nonstick cooking spray.
Combine cream cheese, powdered sugar, limeade concenrate and vanilla in large bowl; beat until well blended. Tint with green food coloring; beat until well blended. Set aside.
2Prepare cake mix according to package directions using 1 egg, water and oil. Spoon batter into prepared muffin cups, filling half full. Spoon 1 rounded teaspoon cream cheese mixture in center of each cup.
Bake about 20 minutes or until tests done with toothpick. Cool completely on wire racks.
3Add 4 drops food coloring to frosting. Stir until well blended; adjust color as needed by adding more coloring 1 drop at a time; blending well after each addition. Spread frosting on cooled cupcakes. Sprinkle with sugar.