- Prep Ingredients: Cube bread, chop veggies, and shred cheese. 
- Cook Sausage: Brown sausage in olive oil, seasoning it with rosemary or Italian seasoning. 
- Sauté Veggies: Cook onion, garlic, bell peppers, mushrooms, and spinach in the same skillet until tender. 
- Assemble: Layer bread in a greased 9x13-inch baking dish, followed by sausage, veggies, and cheese. 
- Prepare Egg Mixture: Whisk eggs, milk, salt, and pepper. Pour evenly over the layered ingredients. 
- Refrigerate: Cover and refrigerate for 1 hour or overnight to let flavors meld. 
- Bake: Preheat oven to 375°F (190°C). Bake uncovered for 40–45 minutes, or until the top is golden brown and the center is set. 
- Serve: Let it rest for 5–10 minutes, then slice and enjoy!