Step 1: Fill a large, deep pot with water (about 4-5 inches deep) and add 1-2 tablespoons of white vinegar. Bring the water to a gentle simmer, just below boiling.
Step 2: Crack each cold egg into individual small bowls or ramekins.
Step 3: Using a slotted spoon, create a gentle swirl in the simmering water. Carefully slide one egg at a time into the center of the swirl. Poach for 3-4 minutes for a runny yolk, or 5 minutes for a slightly firmer yolk. Remove with the slotted spoon and place on a paper towel-lined plate to drain excess water. Repeat with remaining eggs.
Step 4: While eggs are poaching, prepare the hollandaise. In a heatproof bowl placed over a saucepan with simmering water (ensure bowl does not touch water), whisk together 3 large egg yolks, 1 tablespoon fresh lemon juice, a pinch of salt, and a pinch of cayenne pepper.
Step 5: Continuously whisk the egg yolk mixture vigorously for 3-5 minutes, until it becomes light in color, thickens, and doubles in volume. Remove from heat.
Step 6: Slowly, in a thin, steady stream, gradually pour the warm melted butter into the egg yolk mixture while continuously whisking until all the butter is incorporated and the sauce is thick, smooth, and glossy. Keep warm.
Step 7: Split 4 English muffins in half and toast them until golden brown. In a small skillet, quickly sear 8 slices of Canadian bacon over medium heat until lightly browned and warmed through, about 1-2 minutes per side.
Step 8: To assemble, place two toasted English muffin halves on a plate. Top each half with one slice of Canadian bacon, then a poached egg. Generously spoon the warm hollandaise sauce over each poached egg. Garnish with fresh chopped chives or parsley and a dash of paprika if desired. Serve immediately.