Preheat oven to 350 degrees F (175 degrees C). Grease an 8-inch baking pan with cooking spray.
Whisk eggs and sugar in a large bowl. Stir in milk; whisk until well combined. Add bread cubes; stir to moisten. Mix in chocolate-covered raisins. Spoon mixture in the prepared baking pan; let it sit for 10 minutes to allow flavors to blend.
Bake in the preheated oven until set, 55 to 60 minutes.