In a medium sized mixing bowl whisk together egg and milk until well combined. Add in cheese, diced bell pepper, tomatoes and Chorizo if you are using it. Season with salt and pepper.
Grease a microwave safe mug with cooking spray, pour egg mixture into mug filling it about 1/2 way. Don't overfill or they can overflow and make a big mess as you cook them.
Cook 1 minute, remove from microwave, stir and cook another minute or until done to your taste. Don't worry if they are a little wet when you take them out of the microwave, they will continue to set as they cool. Let site one minute to cool off, these are hot! Top with Salsa and additional cheese if you wish, or wrap them in a warmed flour tortilla for a 2 minute breakfast burrito.