It’s a special time of year when blood oranges are in season. Garnet. Ruby. Crimson. Blood. RED. They are superbly sweet, slightly tangy, and a whole lot of citrusy. They are delicious. And so is vanilla cake. Thus, we must. Mix, match, meld.. …bake a cake. Blood Orange Vanilla Cake 2 1/4 cups ​all-purpose flour…