Heat oven to 350°F (180°C). Grease or spray two 8-inch (20 cm) round cake pans; place 8-inch (20 cm) round piece of cooking parchment paper in bottom of each pan. Grease or spray parchment paper. In large bowl, beat 1 box cake mix and ingredients called for on box with electric mixer on low speed 30 seconds, then on high speed about 2 minutes or until smooth. Spread in pans. Bake as directed on box. Cool 10 minutes; run knife around sides of pans to loosen cakes. Gently remove from pans to cooling rack; remove parchment paper. Cool completely, about 30 minutes. Meanwhile, repeat to make 2 more layers.