Preheat oven to 350 °F (175 °C). Spray a 9‑inch round or square baking pan with non‑stick spray.

Open the cinnamon roll can and separate. Reserve the icing packet for after baking. Cut each roll into 6 pieces and arrange the pieces evenly in the prepared pan.

Sprinkle the blueberries evenly over and between the cinnamon roll pieces.

In a small bowl, combine the melted butter and brown sugar. Pour this mixture evenly over the cinnamon roll pieces and blueberries.

Bake for 25–35 minutes, or until golden brown and cooked through.

Remove from oven and immediately drizzle the reserved icing over the hot casserole. Let sit a few minutes to set slightly before serving.