Heat oven to 350°F (325°F for dark or nonstick pan). Grease bottom only of 13x9-inch pan, or spray with baking spray with flour. Generously grease 5-inch round ovenproof bowl (that holds at least 1 cup), or spray with baking spray with flour.
Make cake batter as directed on box. Pour 1/2 cup batter into greased bowl; pour remaining batter into pan.
Bake bowl 19 to 24 minutes and pan 26 to 33 minutes or until toothpick inserted in center comes out clean or cake springs back when touched lightly in center. Cool cakes 10 minutes. Turn upside down onto cooling rack to remove cakes. Cool completely, about 60 minutes. Chill cakes in refrigerator or freezer 30 to 60 minutes before cutting to reduce crumbs. Place bottom side up on serving tray.
Spoon 1/2 cup of the vanilla frosting into resealable food-storage plastic bag. Seal bag; set aside. In medium bowl, stir together remaining vanilla frosting and the chocolate frosting.
Using serrated knife, cut cake into gingerbread boy shape (see diagram). Spread cut edge of neck with frosting; attach round piece for head. To seal crumbs, frost cake with a thin layer of frosting. Refrigerate or freeze 30 to 60 minutes to set frosting. Spread remaining frosting evenly over cake. Cut off small corner of bag containing vanilla frosting. Pipe frosting onto cake to decorate as shown in photo. Store loosely covered.