Fill a small pot with water and bring to a slow boil. While you wait for the water to boil, prepare the hollandaise sauce according to the package directions. Toast the English muffins according to the package directions.
Once the water is boiling, add vinegar. Whisk the boiling water in a circular motion to form a whirlpool effect.
While water is swirling, crack eggs and drop them one at a time into the water.
Allow water to return to a boil and then reduce heat to simmer. Cook eggs until desired firmness (about three minutes).
Layer toasted English muffin halves with spinach and prosciutto.
Gently remove eggs from water with a slotted spoon and place on top of the prosciutto.
Drizzle with hollandaise sauce. Serve.