Spray a large microwave-safe mug with nonstick spray. Add green pepper and onion and microwave until softened, 1 to 2 minutes.
Blot any excess liquid from the vegetables. Add egg substitute and microwave for 1 minute.
Add ham and cheese and lightly stir. Microwave until scramble is just set, an additional 45 to 60 seconds.
Let cool slightly. Garnish with orange slices and serve with an English muffin, if using. Eat up!