Preheat oven to 350°F. Lightly grease or line standard or mini muffin pan with paper liners.
For Cake: In a large bowl, stir together cake mix, water and butter until well blended. Spoon batter into prepared muffin pan, filling 2/3 full.
For standard size cupcakes, bake 22-23 minutes; for mini cupcakes, bake 18-20 minutes or until toothpick inserted in center comes out clean. Cool completely before applying glaze.
For Lemonade Glaze: In small bowl, place lemon glaze mix, and lemonade. Stir with a whisk until smooth. Drizzle over cooled cupcakes. Sprinkle with zest, if desired. Makes 12 standard size cupcakes or mini 24 cupcakes.