Prep: 20 min., Bake: 20 min.
Beat softened cream cheese and next 3 ingredients at medium speed with an electric mixer until blended. Set mixture aside.
Prepare cake batter according to package directions.
Place 36 paper baking cups into muffin pans. Spoon 1 tablespoon cake batter into each paper cup in pan; top each with 1 tablespoon cream cheese mixture. Top cream cheese mixture with 1 tablespoon cake batter.
Bake at 350º for 20 minutes. Cool in pans on wire racks 10 minutes; remove from pans, and let cool completely on wire racks. Sprinkle cupcakes with powdered sugar.
Chocolate-Cream Cheese Tunnel Cake: Prepare cream cheese mixture as directed. Prepare cake mix as directed. Pour half of cake batter into a greased and floured 10-inch tube pan. Top batter in pan with cream cheese mixture, forming a ring. Pour remaining cake batter into pan. Bake at 350º for 45 minutes or until a long wooden pick inserted in center comes out clean. Cool in pan 30 minutes on a wire rack. Remove cake from pan; place on a serving platter, and let cool completely.