1. Beat softened cream cheese and next 3 ingredients at medium speed with an electric mixer until blended. Set mixture aside.
2. Prepare cake batter according to package directions.
3. 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.
4. 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.