Step 1

1 Heat oven to 375° F (350° F for dark or nonstick pan). Line bottom only of 15x10x1-inch pan with cooking parchment paper. Spray with baking spray with flour. Place paper baking cups in 6 regular-size muffin cups.

Step 2

2 In large bowl, beat eggs with electric mixer on high speed about 6 minutes or until thick and lemon colored. Add cake mix, water and oil; beat on low speed 30 seconds, then on medium speed 1 minute. Pour 3 1/2 cups batter into pan. Divide remaining batter among 6 muffin cups.

Step 3

3 Bake 14 to 16 minutes or until cake springs back when lightly touched in center and cupcakes test done when toothpick inserted in center comes out clean. Immediately turn cake upside down onto clean kitchen towel sprinkled with 1/4 cup powdered sugar; peel away parchment paper. While still hot, carefully roll up cake and towel from narrow end. Cool rolled-up cake 10 minutes at room temperature, and then about 1 hour in refrigerator. Cool cupcakes 10 minutes. Remove from pan; cool completely, about 30 minutes. Save cupcakes for another use.

Step 4

4 Unroll cake carefully, and remove towel. Allow the end to remain slightly curled. Spread 1 container frosting evenly over cake's surface. Re-roll filled cake, wrap in plastic wrap and refrigerate 30 minutes.

Step 5

5 Pour 1 cup rainbow candy sprinkles in large pan with sides. Remove cake from refrigerator, unwrap and frost top and sides with 1/2 container frosting. Using spatula and one hand, lift cake into pan, and gently roll in sprinkles. Transfer cake to serving platter. Decorate with colorful picks and birthday candles. Store loosely covered in refrigerator. Let stand at room temperature 30 minutes before serving.