Blueberry Upside Down Cake

From the blogger: "The ultimate cake for blueberry lovers! A tender, delicious cake perfect with a dollop of whipped cream. This easy blueberry upside down cake is simple to make with cake mix, blueberries, brown sugar, and butter. The caramelized berry topping makes it extra special adding tons of moisture and flavor over a tender cake base. This blueberry version comes out of the pan a lot easier than other upside down cakes I have made. Not sure if it’s because blueberries are so much smaller or what the reason is, but it’s another checkmark on the list of why this cake is one of our favorite variations to make. "

Cooking Vessel Size13x9 Baking Dish, baking sheet