Line 18 muffin cups and 12 mini muffin cups with paper baking cups.
Prepare cake mix according to Egg White Recipe package instructions using water, oil and egg whites. Divide into prepared baking cups and mini baking cups. Bake and cool according to package instructions, reducing bake time for mini cupcakes to 11 to 12 minutes.
Spoon frosting into large pastry bag fitted with large open star tip. Beginning at center of cupcakes, pipe frosting in a tight, circular pattern, gradually moving toward outside edge. Arrange cupcakes in decorative bowl(s) or other container(s) to resemble a bouquet. Garnish with mint sprigs and leaves.