Preheat oven to 350 ºF. Line two 15.5 x 10.5 x 1-inch jellyroll pans with aluminum foil.
Prepare cake mix as directed on package. Divide and spread evenly into pans. Cut through batter with knife or spatula to remove large air bubbles.
Bake 15 minutes or until set. Invert cakes at once onto clean, lint-free dishtowels dusted with confectioners’ sugar. Remove foil carefully. Roll up each cake with towel jelly-roll fashion, starting at short end. Cool completely.
Unroll cakes. Spread about 1 cup blueberry pie filling to within 1 inch of edges on each cake. Reroll cake only and place seam-side down on serving plate. Dust with 1/4 cup sugar. Garnish with mint leaves, if desired.