1-First, grease a 9×13 inch or similar sized oven-safe casserole dish and spread the 4 cups of bread cubes evenly in the bottom. This creates a solid base that absorbs flavors beautifully.

2-Next, heat 1 teaspoon of olive oil in a large skillet over medium heat and add the 1 pound of ground pork sausage along with 1 teaspoon of dried rosemary if you’re using it.

3-Break the sausage into bite-size pieces and cook until almost done, then mix in the 3/4 cup of chopped yellow onion, 2 minced garlic cloves, 2 cups of chopped bell peppers, 1 cup of sliced mushrooms, and 1 cup of roughly chopped fresh spinach. Cook this for about 5 to 6 minutes until everything softens and the sausage is fully cooked.

4-Spread this mixture over the bread cubes in the dish. In a separate bowl, whisk together the 12 large eggs, 1/4 teaspoon salt, 1/8 teaspoon black pepper, 2/3 cup of milk or half-and-half, and 1 cup of shredded cheddar cheese. Pour it evenly over the layers, sprinkle a bit more salt and pepper on top, and cover to refrigerate for at least 30 minutes or up to 24 hours.

5-When it’s time to bake, preheat your oven to 375°F and let the dish sit at room temperature for 10-15 minutes. Bake uncovered for 40 to 45 minutes until golden and set, then cool for 10 minutes before serving. Leftovers store well for up to 5 days, making this a great make-ahead option.