Prepare cake mix batter according to package directions. Fill paper-lined jumbo muffin cups three-fourths full. Bake according to package directions for 24-28 minutes or until a toothpick inserted in the center comes out clean. Cool for 10 minutes before removing from pans to wire racks to cool completely.
In a small bowl, beat 1/2 cup cream until stiff peaks form; set aside. In a large bowl, combine the ricotta cheese, confectioners' sugar, Mascarpone cheese and extract until smooth. Fold in pistachios and the whipped cream.
Cut the top off each cupcake. Spread or pipe cupcakes with cheese mixture; replace tops. In a small saucepan, melt white baking chocolate with remaining cream over low heat; stir until smooth. Remove from the heat. Cool to room temperature. Spoon over cupcakes; sprinkle with chocolate curls. Refrigerate leftovers.