STEP 1:
Whisk flour, baking powder & salt & set aside. Mix butter & sugar. Add in oil & beat for another minute. Add egg whites one at a time & beat. Add sour cream & vanilla extract & beat.
STEP 4:
Wash, hull and dice the strawberries. Bring sugar and water to a light boil, reduce the heat & let it simmer for 3 min. Pour syrup over strawberries, let it cool & refrigerate.
STEP 5:
Mix butter & cream cheese. On low speed, add half the powdered sugar, then the rest of the powdered sugar, vanilla & salt. Frost the cake & top with strawberry topping.