Prepare a 9x13 pan with a baking spray (not just an oil spray) or grease and flour the pan.
In a large mixer bowl, beat eggs, oil, vanilla, and sugar on medium speed until smooth.
Add in flour, baking powder, baking soda, salt, cinnamon, nutmeg, and ginger.
Slowly pour in milk and mix on low to combine.
Stir in carrots and walnuts until well-mixed. (If using additional items add them now)
Pour batter into the prepared cake pan.
Bake at 350° degrees for 20-30 minutes or until a toothpick comes out clean.
Allow the cake to cool for 15 minutes, or until the pan is cool to the touch, then turn it out onto a cooling rack.
Place on serving plate, or leave in pan.
Cool completely before icing.
In the bowl of a mixer whip butter and cream cheese, then add powdered sugar, cream, and vanilla (salt if adding) until smooth.
Portion out a small amount of frosting to tint some with orange food coloring and a couple of tablespoons of frosting to tint green.
Spread cream cheese frosting over the cooled cake with an offset spatula or with the back of a spoon creating a little swirl.
Then pipe on the carrot design and stem.