Prepare the Hollandaise Sauce:
In a heatproof bowl over simmering water (double boiler), whisk together the egg yolks and lemon juice until thickened. Slowly drizzle in melted butter, whisking constantly, until the sauce is smooth and creamy. Season with salt and cayenne pepper. Keep warm.
Alternatively, blend egg yolks and lemon juice in a blender, then slowly stream in melted butter while blending.
Cook the Canadian Bacon:
Heat a skillet over medium heat and cook the Canadian bacon until lightly browned. Set aside and keep warm.
Poach the Eggs:
Fill a saucepan with water and bring it to a gentle simmer. Add a tablespoon of vinegar if desired.
Crack each egg into a small bowl and gently slide it into the simmering water. Poach for 3-4 minutes for a runny yolk or longer for a firmer yolk. Remove with a slotted spoon and drain on a paper towel.
Assemble the Eggs Benedict:
Place a slice of toasted English muffin on each plate. Top each half with a slice of Canadian bacon, a poached egg, and a generous drizzle of hollandaise sauce.
Garnish and Serve:
Sprinkle with fresh chives or parsley and serve immediately.