Canned crescent dough is the secret to making this flaky treat truly effortless.
Mix together the egg, milk, and cheese in a small bowl. Spray an oven safe mug with cooking spray. Place the croissant dough inside the mug to cover the bottom and sides. Pour the egg mixture over the dough. Fold the tips of the dough over the egg mixture, joining with the dough on the other side. Bake for 25-30 minutes at 350°.