Use one 5-inch and one 12-inch Dutch oven with 34 briquettes.
–International Dutch Oven Society
Combine the cream cheese, milk, sugar, and vanilla in the 5-inch Dutch oven. Simmer and stir until consistent, then set aside. Lightly spray or coat the inside of the cold 12-inch Dutch oven with olive oil. Pour into it the white cake mix and ginger ale and stir until blended. Add the blueberries and cream cheese mixture. In a separate bowl, mix together the sugar cookie mix, egg substitute, and butter. Add this to the 12-inch Dutch oven and cover.
Place the 12-inch oven over 12 briquettes, with 22 briquettes on the lid. Bake for 50 to 60 minutes, with quarter rotations of the oven and lid every 15 minutes.