Bake two round cakes according to instructions on box. Allow to cool. SEE NOT ABOUT CAKE PAN SIZES.
Beat cold butter using an electric mixer for 2 minutes.
Add sifted powdered sugar and mix until creamed.
Beat in heavy whipping cream and vanilla.
Add lemon extract, if desired.
Add 6 drops of red liquid food coloring. Mix.
Mix by hand to remove any air bubbles. Reserve 1/4 c. frosting for later.
Slice cakes in half using cake leveler. Place one layer on a plate that has a small amount of frosting on it to keep the cake from sliding. Spread top with frosting. Add a layer of strawberry preserves, if desired.
Stack the second layer. Repeat with frosting and preserves.
Stack the 3rd layer. Repeat with frosting and preserves.
Stack the 4th layer. Frost with a crumb coat. Freeze cake for 10 minutes.
Pour remaining frosting on top of cake and push excess down the sides until the cake has been completely covered and frosted.
Add a small amount of frosting to the bottom of the unicorn topper. Press topper into place on top of cake.
Press eyelashes onto cake.
Dip flowers into excess frosting and press onto cake.
Poke a straw into the cake, leaving about 3" sticking out.
Place pig snout over straw. Trim until the straw is just holding the snout up. Press snout into cake gently. It will rest on the straw.
Add sprinkles around the base of the cake.