Beat eggs in large bowl with mixer on high speed 5 min. (Eggs should be frothy and lemon coloured.) Add cake mix, water and oil; beat on low speed 30 sec., then beat on medium speed 1 min. Pour 3-1/2 cups batter into prepared pan; spread to evenly cover bottom of pan. Gently tap filled pan on counter to remove any air bubbles. Spoon remaining batter into 6 paper-lined muffin cups.