How to make a homemade Disney Cars Theme Cake

My son, and my nephew share their birthday week, and I made an adorable Disney Cars themed cake for their 3rd Birthday party this past May - they each took a turn blowing out the candle.  It was so simple to make and turned out adorable, I just had to share it.

First, I baked a Pillsbury brand box cake mix in a rectangle cake pan with a few additions of lemon rind, a about 2 teaspoons of lemon juice and a dash of real vanilla.  I used a store-bought can of Pillsbury white whipped frosting.  I separated the frosting into 2 bowls using 1/3 in the first bowl, and the remaining 2/3 in the second bowl.  I used a hand mixer on low then med-high speed to fluff the frosting and also to mix the colors.  The hand mixer fills the frosting with air and allows you to use much less and still get the taste you desire without the cake being overly sweet.  The smaller bowl I used a mixture of red, green and blue food coloring until I achieved a grey color similar to a road.  The larger bowl, I used a green and a lime green food color to get a nice bright green for the grass.  I started with the grey color, and made a curvy "T" of frosting on the cake using just a butter knife, starting with a thin crumb layer, then adding some more frosting.  I then filled in the rest of the cake with the green color to the sides.  I then added blueberries along the road line to create a separation of colors and to also hide any imperfections in my lines.  I used 3 yellow mini M&M's for each of the road lines.  I added 3 of my sons Daisey Cars die cast vehicles (sanitized first in the dishwasher).  For fun, I used a package of Cars themed fruit snacks to add some to the corners of the roads.  I used corkscrew candles which turned out so cute.  It was a hit, as you can tell by the look on my sons face (the blondie).