Spray inside of your slow cooker with nonstick cooking spray.
In a large bowl, stir blueberries, sugar and cornstarch. Stir in vanilla. Pour blueberry mixture into your slow cooker.
In a large bowl, combine cake mix and melted butter. Crumble over blueberries.
Cover slow cooker with a double layer of white paper towels. Secure lid onto your slow cooker. Cook on Low, until topping is set, about 3-4 hours.
Serve with scoops of vanilla ice cream (if desired).
Enjoy!
Notes
TIPS• Don't want to use cake mix? Combine 1-1/2 cups all-purpose flour, 3/4 cup sugar, 1/4 cup milk powder, 1 teaspoon baking powder, 1/2 teaspoon kosher salt in a medium bowl. Use in place of cake mix in the recipe.• Want more flavor? Stir 1/2 teaspoon of fresh lemon zest into your blueberry mixture. This really brightens up the blueberries.• Using paper towels under the lid will catch condensation and keep it from dripping on the cobbler topping.