Gluten free dairy free Chocolate Lego Cake

For my four year olds birthday he begged for a Lego Cake . I search the Internet and got ideas . It had to be gluten free and dairy free .
I have finally after reading several sites perfected a gluten free cake .I tweaked it to the ingredients I use.
I made my own gluten free flour blend,

 Cake Flour Blend

Yield: Approximately 3 cups

Ingredients:

• 1 1/4 cup superfine white rice flour (I use Bob's Red Mill))
• 3/4 cup potato starch
• 1/2 cup sorghum or oat flour
• 1/4 cup superfine brown rice flour (or more superfine white rice flour)
• 1/4 cup tapioca starch
• 1 1/2 teaspoons baking soda (for  chocolate cake use 2)
• 2 teaspoons gluten-free baking powder
• 2 teaspoons xanthan gum (or guar gum for corn-free)

Instructions:

1. Mix all ingredients well by whisking and shaking. For best results sift together one to two times.
2. Tips

If you are making a yellow or white cake you may consider using more white rice flour in place of the brown rice flour, as the mix above makes it a tiny bit brown. Though sorghum is a bit on the brown side, this recipe uses very little and does not effect the yellow color of cake. If using this gluten free cake flour blend to substitute regular all-purpose flour in a recipe I suggest baking at 350°F, no matter what the recipe calls for, and adding a bit more fat: oil, butter, etc.

I made my own gluten free baking mix.

For the Chocolate Cake FOR THE LEGO CAKE I DOUBLED THIS
• 1 3/4 cup  Gluten-free Cake Flour
• 1 1/3 cups sugar or evaporated cane juice
• 3/4 cup raw cacaou  
• 1 teaspoon salt
• 1/2 cup oil (I used coconut oil and earth balance melted)
• 3/4 cup boiling water
• 1 cup milk, room temperature or 80°F. I used coconut milk
• 2 eggs, at room temperature
• 1 egg white, at room temperature
• 2 teaspoons vanilla extract
• Superfine white rice flour, for dusting
 

Instructions:

To Make the Cake:
1. Heat oven to 350°F.
2. Oil and dust with superfine rice flour, two 9-inch round cake pans. (Doubled I used a 9x13 and also made cupcakes because it was a lot)
3. In the bowl of your mixer, mix together all dry ingredients.
4. Add milk, oil, and eggs; and beat on medium speed until smooth.
5. Add in boiling water and mix on low until well blended; add vanilla and blend again.
6. Bake about 30 minutes or until it is toothpick clean.
7. Remove from oven and cool for 10-15 minutes; and remove from pans by turning it upside down onto your hand and then transfer down side down onto a cooling rack. Cool completely.

For Frosting I used a basic butter cream recipe but used spectrum non hydrogenated shortening. For colors I used beet powder, green matcha tea powder and turmeric. I had to adjust by adding more until I achieved the color I wanted.

This top photo one of the pieces broke so I held it together with frosting. I baked in a 9x13. Cut the cake into thirds. And cut one of the thirds in half. I used natural marshmallows cut in half for the top of the cake.