Combined the blueberries and pineapple in the 3 Quart Saucepan.
Whisk together the cake mix and cinnamon in a bowl. Sprinkle the mixture evenly over the fruit.
Cover the pot and cook over medium heat until vapor begins to escape from the lid, about 5 minutes.
Spin the lid to engage the Vapor Seal, then immediately reduce the heat to low. Cook for about 20 minutes or until the fruit is bubbly and the topping is firm to the touch.