Preheat the Oven:

1. Preheat your oven to 350°F (175°C).

Prepare the Baking Dish:

1. Grease a 9×13-inch baking dish with cooking spray or butter.

Mix the Eggs and Cream Cheese:

1. In a large mixing bowl, add the softened cream cheese, eggs, milk, salt, pepper, garlic powder, and onion powder. Use a hand mixer or whisk to blend them until smooth and creamy.

Prepare the Vegetables:

1. In a separate bowl, combine the diced bell peppers, cooked spinach, diced onion, cherry tomatoes, and crumbled sausage or bacon (if using). Mix well.

Combine Ingredients:

1. Fold the vegetable mixture into the egg and cream cheese mixture until well incorporated.

Add Bread and Cheese:

1. On the bottom of the greased baking dish, layer the cubed bread evenly. Pour the egg mixture over the bread, ensuring an even distribution. Top with the shredded cheese.

Bake:

1. Bake in the preheated oven for 40-45 minutes, or until the casserole is golden and set in the center. A toothpick inserted should come out clean.

Cool and Serve:

1. Let the casserole cool for about 10 minutes before slicing. Serve warm, garnished with fresh herbs if desired.