In a medium bowl, whisk together the egg, spinach, red bell pepper, black pepper, and salt.
2. Step
Heat a nonstick pan over medium heat. Place a greased mason jar lid right-side up in the pan. Slowly pour the egg mixture into the lid. Cover the pan and cook for 3 minutes, until the egg has set on the bottom.
3. Step
Remove the cover and use a fork pull the lid off of the egg. Flip the egg and cook for another 3 minutes, until cooked through.
4. Step
Place the egg patty on the English muffin and top with the sliced avocado.
