First, prepare the croissants. Cut them in half, spread some Nutella inside, and place some banana slices on top. Repeat with all.

Spray a 9x13 dish with baking spray, and arrange the stuffed croissants inside.

In a small bowl, whisk together the milk, eggs, vanilla, sugar, and cinnamon.

Pour mixture over the croissants, making sure that they are mostly submerged. Cover with plastic wrap, and place in fridge overnight.

When ready to bake, preheat oven to 350F. Bake for 50-55 minutes, until cooked through and no longer jiggly. Serve warm!