Heat oven to 400 degrees.
In the bowl of a kitchenaid, mix the flour and sugar.
Place the margarine, shortening and water in a saucepan over medium heat and bring it to a light boil.
In a separate bowl, combine the buttermilk, eggs, soda, vanilla and salt, whisk until smooth.
Take the shortening mixture and pour it over the flour mixture and mix until smooth. add the buttermilk mixture and mix again until smooth.
Lightly spray a cookie sheet with cooking oil (pam).
pour the mixture in the pan and bake for 20 minutes.
Allow to completely cool.
Frost the cake with the whipped cream frosting.
Decorate the cake with blueberries in one corner and two rows of raspberries all the way across the cake, skipping a stripe for the white stripe and repeating.
Pipe white stripes using the butttercream between the raspberries and as little stars between blueberries.