1Heat oven to 350°F (325°F for dark or nonstick pans). Place paper baking cup in each of 24 regular-size muffin cups.
2Make cake batter as directed on box. Divide batter evenly among muffin cups (two-thirds full). Place ice cream cone upside down on batter in each cup.
3Bake 16 to 22 minutes or until toothpick inserted in cake comes out clean (cones may tilt on batter). Cool completely, about 30 minutes. Remove paper baking cups. Generously frost cake with frosting, and decorate as desired. Store loosely covered.