1. Cook breakfast sausage in a skillet until browned, drain excess fat, and let cool.

2. Grease a 9×13-inch baking dish with butter or nonstick spray.

3. In a large bowl, whisk together eggs, milk, dried thyme, salt, and pepper until frothy.

4. Layer bread cubes evenly in the prepared baking dish.

5. Sprinkle cooked sausage, diced bell pepper, and chopped onion over the bread.

6. Pour the egg and milk mixture evenly over the layers.

7. Sprinkle shredded cheddar cheese on top.

8. Cover the dish tightly with foil and refrigerate for at least 8 hours or up to 24 hours.

9. When ready to bake, preheat oven to 350°F (180°C).

10. Place the covered casserole in the oven and bake for 30 minutes.

11. Remove foil and bake an additional 15–20 minutes until the top is golden and the center is set.

12. Let rest for 5 minutes before slicing and serving.