Heat a skillet over medium heat and coat with cooking spray. Crack one egg onto skillet and sprinkle with salt and pepper to taste. After about 1-2 minutes (depending on how runny you want the egg) carefully flip the egg over. Sprinkle again with salt and pepper, remove from heat after another 45 seconds to 1 minute.
To assemble sandwich:
Place toasted English muffin on plate, layer with spinach (optional), egg, avocado slices, then grate on some fresh Parmesan (optional). Enjoy!