Step 1: For the Poached Eggs: Fill a large saucepan with about 3-4 inches of water. Add 1 tablespoon white vinegar and a pinch of salt. Bring to a gentle simmer, just below a boil.
Step 2: Crack each of the 4 eggs into separate small bowls or ramekins. Gently swirl the simmering water with a spoon, then carefully slide each egg into the center of the swirl. Cook 3-4 minutes for runny yolks, or 5 minutes for softer yolks. Do not overcrowd; cook in batches if necessary.
Step 3: Using a slotted spoon, carefully remove the poached eggs and place them on a paper towel-lined plate to drain excess water. Trim any wispy edges if desired. Keep warm while preparing other components.
Step 4: For the English Muffins & Canadian Bacon: Split the English muffins in half using a fork. Toast them until golden brown and slightly crispy. Set aside.
Step 5: Heat a non-stick pan over medium heat. Add the Canadian bacon slices and cook for 1-2 minutes per side, until lightly browned and heated through. Keep warm.
Step 6: For the Hollandaise Sauce: Melt 1 cup (2 sticks) unsalted butter in a small saucepan over low heat. Keep it warm. In a heatproof bowl (preferably stainless steel), whisk together 4 large egg yolks, 3 tablespoons fresh lemon juice, 1 tablespoon cold water, and a pinch of salt.
Step 7: Set the bowl over a saucepan of simmering water (ensure the bottom of the bowl does not touch the water). Continuously whisk the egg yolk mixture vigorously for 3-5 minutes, until it lightens in color, thickens, and can coat the back of a spoon. It should be hot to the touch but not scrambled.
Step 8: Remove the bowl from the heat. Very slowly, drop by drop at first, then in a thin, steady stream, whisk in the warm melted butter. Continue whisking constantly until all the butter is incorporated and the sauce is thick, smooth, and emulsified. If it gets too thick, whisk in a teaspoon of warm water until desired consistency.
Step 9: Stir in a pinch of cayenne pepper (optional) and taste for seasoning, adding more salt or lemon juice if needed. Keep the Hollandaise warm by covering the bowl and placing it over a pan of warm (not hot) water until ready to serve.
Step 10: To Assemble: Place two toasted English muffin halves on each plate. Top each half with a slice of warm Canadian bacon. Carefully place one poached egg on top of each bacon slice.
Step 11: Generously spoon the warm Hollandaise sauce over the poached eggs. Garnish with fresh chopped chives or parsley and a crack of black pepper. Serve immediately.