Preheat Oven: Preheat your oven to 350°F (175°C).
Prepare Cinnamon Rolls: Open the packages of cinnamon rolls and cut each roll into quarters. Spread the pieces evenly in a greased 9x13-inch baking dish.
Add Blueberries: Sprinkle the blueberries evenly over the cinnamon roll pieces in the baking dish.
Make Egg Mixture: In a medium-sized bowl, whisk together the eggs, milk, cinnamon, and vanilla extract until well combined.
Combine Ingredients: Pour the egg mixture evenly over the cinnamon rolls and blueberries in the baking dish. Gently press down on the mixture to ensure the cinnamon roll pieces are soaked with the egg mixture.
Bake: Bake uncovered for 40-45 or until the casserole is set and the top is golden brown.
Add Icing: Once the casserole is done baking, remove it from the oven and let it cool for about 10 minutes. Warm the icing in the microwave for about 10 seconds then drizzle the icing over the top of the casserole.
Serve: Spoon out and serve warm. Enjoy your Blueberry Cinnamon Roll Casserole!