1. Coat a 13 x 9 x 2-inch baking dish with nonstick cooking spray. In bottom of dish, place half of the muffin pieces. Top with half of the ham. Sprinkle half of the cheese over top. Repeat layering using all ham and cheese.
2. In a large bowl or glass measuring cup, whisk milk, egg substitute, mustard, black pepper and salt. Pour over the top of the strata. With a large spatula, gently press down on the top so all ingredients are moistened.
3. Wrap tightly, label and freeze for up to 2 months.To Cook:
4. Thaw in refrigerator overnight.
5. Heat oven to 350 degrees F. Bake strata uncovered at 350 degrees F for 45 to 60 minutes until cheese is melted and golden and strata registers 160 degrees F on an instant-read thermometer.
6. To serve, allow to stand for 10 minutes. Cut into 8 servings. Serve warm or at room temperature with sliced fresh fruit.