Grease a 9×13-inch or any 3–4-quart oven-safe casserole dish.

Arrange bread cubes in an even layer in the bottom of the pan. Sprinkle the tomatoes, bell peppers, and ham evenly on top. Top with the cheese. Set aside.

Whisk the eggs, milk, paprika, ground mustard, salt, and pepper together. Pour evenly over the bread/ham. Top with green onions.

Cover casserole with plastic wrap or aluminum foil and refrigerate for at least 1 hour and up to 24 hours.

When ready to bake, allow to sit at room temperature for 10–15 minutes as the oven preheats.

Preheat the oven to 375°F (191°C).

Bake uncovered for 30 minutes. Loosely cover with aluminum foil and bake for another 15–25 minutes. The strata is done when it has browned on the sides and the center is puffy. Mine usually takes around 50 minutes.

Cool for 10 minutes, top with more green onions and/or pepper, and/or add a sprinkle of chopped parsley or flaky sea salt. Slice and serve.

Leftovers keep well in the refrigerator for up to 5 days. Reheat in the microwave to your liking.