Preheat oven to 350 degrees. Grease and flour a 10-ince tube pan.
Toss blueberries with the reserved cake mix.
Place remaining cake mix, pudding mix, yogurt, oil, water, cinnamon (opt.) and eggs in a large mixing bowl. Beat for 1 minute. Scrape down the sides and beat 2 more minutes. Batter should be thick and well-blended.
Pour 2/3 of the batter into the prepared pan. Scatter blueberries over the batter. Spread the remaining batter over the blueberries so it covers the fruit.
Bake 45 - 50 minutes until golden brown on top and the cake starts to pull away from the sides of the pan.
Cool on wire rack for 20 minutes and turn out so that the cake is right side up.
Cool completely before serving. Dust with 10X sugar, if desired.