Preheat oven to 375 degrees F. Lightly oil a 9 inch round cake pan and set aside.
Place the flour, cornmeal, brown sugar, baking powder, baking soda and salt in a large bowl and mix to combine. In a small bowl, combine the yogurt and milk, and whisk in the eggs, egg white and oil and set aside.
Toss the apples with the cinnamon. Add to the dry ingredients and toss to coat the fruit. Add the yogurt mixture and, using a rubber spatula, mix until just combined. The mixture will be lumpy, but should not be overmixed. Pour the mixture into the prepared cake pan, spreading it out to the edges.
Bake until the cake is golden brown and a toothpick inserted in the center comes out clean, 40 to 45 minutes. Cool in the pan on the rack. When cool, invert the cake onto a cutting board and slice into 8 wedges. Split each wedge in half and toast under a broiler, cut side up. Serve warm.
c.1997, M.S. Milliken & S. Feniger, all rights reserved