Vigorously whisk the egg yolks and lemon juice together in a stainless steel bowl and until the mixture is thickened and doubled in volume.
Place the bowl over a saucepan containing barely simmering water (or use a double boiler,) the water should not touch the bottom of the bowl. Continue to whisk rapidly. Be careful not to let the eggs get too hot or they will scramble.
Slowly drizzle in the melted butter and continue to whisk until the sauce is thickened and doubled in volume. Remove from heat, whisk in salt.
Cover and place in a warm spot until ready to use for the eggs benedict. If the sauce gets too thick, whisk in a few drops of warm water before serving.
Fill a pan half full of water. Add vinegar to the cooking water. Bring to a slow boil.
Gently break 1 of the eggs into the water taking care not to break it. Repeat with remaining eggs. Reduce the heat to a gentle simmer.
Remove from heat, cover, and let cook for 4 minutes. Remove with a slotted spoon, allowing the egg to drain.
To assemble: Set up open and toasted English Muffin. Add ham to each side of the muffin and top with poached egg. Drizzle hollandaise sauce over the top of egg and muffin and serve!