Cook the bacon according to package directions. Remove from pan and blot with paper towels so it'll be crispy. Also blot the tomatoes with paper towels to remove excess moisture.
Toast the English muffin. Meanwhile, cook the egg over easy in a small, nonstick skillet sprayed with cooking spray. While the egg is cooking, season it with the salt and pepper.
To assemble, spread one toasted English muffin half with mayo. Layer one piece bacon, the tomato, avocado, the egg, and the second piece of bacon. Spread the second English muffin half with dijon, and top the sandwich. Yields 1 serving.