Spray the inside of the omelet maker with non-stick cooking spray.
Add the red peppers, onion, and diced ham. Close the omelet maker.
Place into the microwave and microwave for 1 minute. My microwave is 900w and I did it on high. The peppers and onions will still have a slight crunch to them. Remove from the omelet maker and place into a bowl.
Add the 3 eggs and milk into the omelet maker. Using a fork, whisk until thoroughly incorporated.
Keep the omelet maker open. Place into the microwave and microwave for 4 minutes 30 seconds. Check it at 4 minutes to see if all of the eggs are cooked. If they are, don't bother with the extra 30 seconds.
Add 1 slice of cheese, the steamed red peppers, onions, and ham.
Fold the omelet over. You can microwave for 10 seconds to melt the cheese if needed.
Add the last slice of american cheese to the top of the omelet and let melt. Place on the plate and serve.