Preheat the oven to 350°F or 175°C and coat a 9-inch baking dish with nonstick spray. Open the cinnamon roll cans and reserve the icing packets.
Cut each cinnamon roll into four pieces. Place the pieces in the baking dish and scatter the diced apples evenly among them.
Sprinkle brown sugar and cinnamon across the dough and fruit. Use clean hands or a spoon to distribute the ingredients without compressing the rolls.
Whisk the eggs, milk, vanilla, and melted butter in a bowl. Pour the mixture slowly over the dish so it reaches the lower pieces.
Cover loosely with foil and bake for 20 minutes. Remove the foil and continue baking for 12 to 18 minutes, until the center is set and the top is golden.
Let the bake cool for 5 minutes, then drizzle the reserved icing over the warm surface. Serve while the rolls are soft and the glaze is still slightly melted.