Strawberries and rhubarb are such a powerful combination. They compliment each other in such a perfect way, it is hard to compete with anything else. This cake is truly spectacular. After a few tweaks and adjustments, I think I have finally come up with a cake version of the strawberry rhubarb pie. This cake is moist, with a delicate crumb. It has a slight sour component from the buttermilk that is fantastic.