Combine cake mix, eggs, applesauce and yogurt in a large bowl; mix well.
Toss blueberries in flour to coat in a small bowl; add 2 cups batter and mix well. Pour 1/2 of batter into greased and floured 10-inch tube pan; top with remaining blueberries.
In a small bowl, combine cinnamon with sugar, stir in nuts; mix well.
Sprinkle mixture over blueberries.
Top with remaining batter.
Bake at 350°F degrees for about 1 hour. Cool in pan for 15 minutes; invert onto a rack and cool completely.
Cut into slices and serve topped with whipped topping or vanilla ice cream, if desired.
12 slices.
