My mom has a "Crazy Cake Recipe" and it wasn't developed for allergies-- she has been making it for about 35 years:
3 Cups Flour
2 Cups Sugar
6 Tablespoons Cocoa
2 Teaspoons Baking Soda
1 Teaspoon Salt
Directions: Mix together then make 3 holes, 2 little and 1 big, in 1 hole put 2 Teaspoons Vinegar in other put 2 Teaspoons Vanilla and in the Big Hole put 2/3 Cup of Oil. Pour 2 Cups Water Over it all and Mix; Bake at 350 degrees for 30-35 minutes. Makes 2 8 or 9” rounds/squares or 1 9x13 rectangle
Here is also an allergy-free No Refrigeration Required Bakery Style Icing:
Ingredients
2 cups shortening
1/2 cup non-dairy powdered coffee creamer
1/2 teaspoon vanilla
1 (32 ounce) package confectioners' sugar, sifted
1/2-3/4 cup water
food coloring, use color of choice (we don't use any)
Directions
1. In a large mixing bowl beat the shortening creamer and extracts.
2. Gradually beat in the confectioners sugar.
3. Add in enough water (starting with almost 1/2 cup) until frosting reaches desired consistency.
4. Add in food coloring until the desired shade is achieved.
**You would have to make sure your vegetable oil and nondairy creamer are soy free :)
By the way- this tastes fabulous :) My 3 year old daughter has peanut, egg, milk and fish allergies.