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

2. Cut the crusty bread into 1 to 1½-inch cubes and spread them evenly in the prepared baking dish. If the bread is very soft, lightly toast the cubes in a low oven for a few minutes to dry them out.

3. Melt 1 tablespoon of butter in a small skillet over medium heat. Add the diced onion and cook until soft and translucent, about 5 minutes. Stir in the minced garlic and cook just until fragrant, about 30 seconds, then remove from the heat to cool slightly.

4. Sprinkle the diced ham evenly over the bread cubes in the baking dish.

5. Scatter the shredded cheddar and mozzarella (or Monterey Jack) over the bread and ham, tucking some of the cheese down between the cubes so it’s distributed throughout.

6. In a large mixing bowl, whisk together the eggs, whole milk, and heavy cream or half-and-half until well combined.

7. Add the sautéed onion and garlic, Dijon mustard, salt, black pepper, and dried Italian herbs or thyme to the egg mixture and whisk again until the seasonings are evenly distributed.

8. Slowly pour the egg mixture evenly over the bread, ham, and cheese in the baking dish, pressing the bread down gently with the back of a spoon so it begins to soak up the custard.

9. Cover the baking dish tightly with plastic wrap or foil and refrigerate for at least 30 minutes or up to overnight to allow the bread to fully absorb the custard.

10. When ready to bake, preheat the oven to 350°F (175°C). Remove the strata from the refrigerator while the oven heats.

11. Dot the top of the strata with the remaining tablespoon of butter if desired for extra color and flavor.

12. Bake uncovered for 40–50 minutes, or until the top is deeply golden, the edges are puffed, and the center is set. A knife inserted in the middle should come out mostly clean.

13. Let the strata rest for about 10 minutes before slicing. Cut into squares and serve warm, garnished with fresh herbs if you like.