Grease a Bundt cake pan with cooking spray or butter; set aside.
In a large bowl or stand mixer, whisk the cake mix, eggs, water, vegetable oil, half of the lemon zest, and the lemon juice until smooth.
Pour the cake batter into the greased Bundt pan and bake for 35 to 40 minutes, or until a toothpick comes out clean when inserted into the center of the cake.
Remove from oven and let the cake cool for 10 minutes in the pan. Then, carefully invert the cake onto a wire rack; let cool.
Once the cake is completely cool, spread frosting as desired over the top. Garnish with lemon zest, and serve.