1Heat oven to 350°F. Place paper baking cup in each of 18 regular-size muffin cups. Make cake batter as directed on box. Fill muffin cups about 3/4 full. Place caramel onto center of batter in each cup; press caramel into batter just until covered.
2Bake 20 to 25 minutes or until tops spring back when touched lightly in center. Cool in pans 10 minutes; remove from pans to cooling rack. Cool completely, about 30 minutes.
3Place frosting in decorating bag fitted with round tip #20. Starting at outer edge of cupcakes, pipe frosting in spiral pattern, gradually elevating to a peak in center; garnish with pretzels.