Preheat the oven to 350°F.
Grease a 9x13-inch baking pan with 1 tablespoon of butter.
4 tbsps. butter
Open the cinnamon rolls and set the icing aside for later. Cut each roll into 4 pieces and spread them evenly in the prepared pan.
2 cans (12.4 oz. each 8 count) refrigerated cinnamon rolls
Melt 3 tablespoons of butter and drizzle it over the cinnamon roll pieces.
Sprinkle 1 cup of blueberries evenly over the cinnamon rolls.
1-1/2 cups fresh blueberries
Evenly sprinkle the brown sugar on top.
1/4 cup light brown sugar
Pour the heavy cream over the entire mixture.
1/2 cup heavy cream
Bake for 35–37 minutes, or until golden brown.
Remove from the oven and let it sit for 5 minutes.
While the casserole cools, combine the icing from both containers in a small bowl. Microwave at 50% power for about 20 seconds.
2 icing containers that came with cinnamon rolls
Stir the icing, then add the remaining ½ cup of blueberries. Using a hand mixer on low speed, blend until smooth.
Drizzle the blueberry icing over the casserole and serve.