In the mixing bowl, add the eggs, milk, salt, ground mustard, and garlic powder. Whisk well to break up all the yolks. Then stir in the cheeses, ham, scallions, and roasted red pepper.
Tear the bread loaf into 1-2 inch chunks and place them in the baking dish.
Pour the egg mixture over the top of the bread. Use a spatula to fold the bread over, gently, to make sure the ingredients are evenly distributed. Cover and chill until ready to bake.
Let the strata recipe rest for at least one hour, so the bread soaks up all the eggs. Preheat the oven to 350 degrees F. (This is a fabulous make-ahead overnight recipe, so you can also preheat the oven in the morning.)
Bake, uncovered, for 50-60 minutes, until the top is golden-brown and puffy in the center. Insert a sharp knife into the center to check that the eggs are set. If not, bake another 5-10 minutes. Then cool for 5 minutes before cutting. Serve warm!
This Strata Recipe make a marvelous leftover meal! Once baked, it will keep in the refrigerator for up to a week.You can also wrap and freeze it for up to 3 months. Then thaw and reheat.