Combine all ingredients in a sauce pan. Cook for 10 minutes until sugar is dissolved. Puree in a blender, then strain. Cool completely or refrigerate overnight.
Cake
Pre-heat oven to 350. Butter and flour a sheet pan.Mix oil, sugar and eggs. Add vanilla, salt, baking soda, baking powder, and flour. Add buttermilk and strawberry puree. Pour into two 9 inch round pans and bake for 45 minutes. Cool on a wire rack.
Frosting
Blend all ingredients for frosting, and frost the cake stacking each layer on top of the other.