Grease and flour two 8 or 9-inch round baking pans and set aside.
In a large mixing bowl mix together all of the dry ingredients: cake mix, pudding, and flour.
Beat in eggs, zucchini, lemon zest, milk and water until well combined.
Pour batter into prepared pans, dividing evenly. Place in oven and bake for 40-45 minutes or center is set and cake is pulling from the edges. You can also use a tooth pick and push it into the center of the cake and when removed it should be clean.
Allow the cakes to completely cool on baking rack.
In the mean time prepare Whipped Lemon Buttercream Frosting.
Whipped Lemon Buttercream Frosting
Using an electric mixer beat butter until smooth, add in lemon zest and powder sugar and mix on low, once the powder sugar is mixed it add in heavy whipping cream and juice from lemon. Beat on high for 3-4 minutes or until frosting is smooth and making soft stiff peaks.
Place one cake layer on a serving plate, I like to use a cake stand.
Assemble layer Cake. Evenly spread the a generous 1/3 of the frosting on top of the bottom layer, then add the second cake on top. Using the remaining frosting, frost the top and the outside of the layered cake. Make sure to spread and frost evenly. Immediately serve or store at room temp.