Heat oven to 375ºF. Coat a shallow 2-qt baking dish with nonstick spray. Spread half the bread cubes over bottom. Cover with half the broccoli, ham, peppers, scallions and cheese. Repeat layer.
Whisk eggs, milk, mustard and pepper in large bowl to blend; pour evenly over strata.
Bake, uncovered, 45-50 minutes until puffed and golden and a knife inserted in center comes out clean. Let stand 5 minutes before serving. Or cover strata with foil and refrigerate 2 hours or overnight, then bake as above. Enjoy!