Green Goddess Dressing:
Place the yogurt, scallions, basil, spinach, lemon juice, garlic, anchovy paste, salt and pepper in a blender or food processor and blend until smooth. (If not using immediately, refrigerate the dressing until ready to serve.)
Egg Sandwich:
Heat 1 teaspoon olive oil in a large skillet over medium high heat. Add the 4 slices of prosciutto to the skillet and cook for 1-2 minutes on each side or until the prosciutto is cooked through and crisp. Set aside on a paper towel-lined plate.
Crack each egg into an individual ramekin or small bowl. Heat the first egg in the microwave for 10-second intervals until it's cooked. Repeat with each egg-filled ramekin. It took me four 10-second intervals to get an egg that was mostly cooked through with a slightly runny yolk that oozes out of the sandwich. Alternately, you can fry the eggs in a skillet.
While the eggs and prosciutto are cooking, toast the English muffins.
To assemble, add 2 tablespoons green goddess dressing to each English muffin. I like to spread one tablespoon on each muffin half. Next, add one egg to the bottom muffin. Top with the prosciutto and a handful of greens. Add the top muffin and your sandwich is ready to devour! Repeat with remaining muffins, eggs, prosciutto, greens and dressing.