Preheat oven to 350°F. Line 30 standard (2-1/2-inch) muffin pan cups with paper baking cups.

Combine all cupcake ingredients in large bowl; beat with electric mixer at low speed 30 seconds. Beat at medium speed 2 minutes.

Spoon batter into prepared muffin cups, filling two-thirds full. Bake 20 to 22 minutes or until toothpick inserted into centers comes out clean. Cool in pans on wire racks 10 minutes. Remove to wire racks; cool completely. (At this point, cupcakes may be frozen up to 3 months. Thaw at room temperature before frosting.)

For frosting, combine mascarpone cheese and 1-1/2 cups powdered sugar in large bowl; beat with electric mixer at medium speed until well blended. Add liqueur; beat until well blended. If frosting is too soft, beat in additional powdered sugar or chill until spreadable.

Frost cooled cupcakes with frosting. Place cocoa in strainer; shake over cupcakes. Store at room temperature up to 24 hours or cover and refrigerate for up to 3 days before serving.