- Preheat the oven to 350°F and lightly butter a 9x13 inch baking dish. 
- Layer half of the croissant pieces in the dish. Top with half the ham and half the cheese. Repeat layers. 
- In a large bowl, whisk together eggs, milk, salt, pepper, garlic powder, and onion powder until smooth. 
- Pour the egg mixture evenly over the layered croissants, ham, and cheese. 
- Gently press down with a spatula to help the croissants soak up the liquid. 
- Bake uncovered for 40 to 45 minutes, until golden brown and set in the center. 
- Let cool for 5 minutes before serving.