Preheat oven to 350 degrees.
Mix flour and baking soda in a medium bowl.
In a large bowl, beat date sugar and applesauce together. Mash bananas and mix in. Add the water and vanilla and mix thoroughly. Add the flour mixture along with the chopped walnuts and stir to mix.
Spread in a 9" X 13" non-stick baking pan. Bake for 40-45 minutes, or until toothpick inserted into the center comes out clean.
While cake is baking, make the macadamia cream by blending the nuts, soy milk, and dates together in a high-powered blender until smooth and creamy.
When the cake is cool, spread the macadamia cream over the top and sprinkle with coconut. Garnish with blueberries and strawberries to create stars and stripes.