Preheat oven to 350°F. Grease a 9x13 baking dish with nonstick spray.

Open cans of biscuit dough and quarter each biscuit. Place in a large ziploc bag.

Add 1 tbsp granulated sugar and 1 tsp cinnamon to the bag. Seal and shake to coat biscuit pieces.

Arrange coated biscuit pieces in an even layer in the prepared baking dish.

In a bowl, whisk together the eggs, 1/3 cup milk, 1 tsp vanilla, and a sprinkle of additional cinnamon if desired.

Pour the egg mixture over the biscuit pieces in the baking dish.

Bake for 30-35 minutes until puffed and golden brown.

Make the glaze by whisking together the powdered sugar, 1 tbsp milk, and 1 tsp vanilla.

Remove casserole from oven and immediately drizzle with the glaze.

Allow to cool slightly before serving warm. Enjoy!