Vanilla Blood Orange Upside Down Cake Serves 10 1/2 cup unsalted butter 3/4 cups firmly packed light brown sugar 2 to 4 vanilla blood oranges, peel and pith removed, and sliced 1/4-inch thick 1. Coat the interior of a 10-inch cake pan with non-stick cooking spray and set aside. 2. Melt the butter in a …