For the hollandaise, whisk 2 large egg yolks, 2 tablespoons of lukewarm water, 2 teaspoons of fresh lemon juice, and ½ teaspoon of Dijon mustard in a small saucepan. Add 8 tablespoons of cubed unsalted butter.
Whisk constantly over low to medium-low heat until the butter melts and the sauce is smooth and thick enough to coat a spoon. Whisk in ¼ teaspoon of fine sea salt and ⅛ teaspoon of cayenne pepper.
Bring a wide pot of water and 1 tablespoon of white vinegar to a bare simmer. Meanwhile, cook 4 slices of Canadian bacon in a skillet until warm and golden; set aside.
Melt 4 teaspoons of unsalted butter in the skillet and toast 2 halved English muffins, cut sides down, until golden.
Crack 4 large eggs into the simmering water, cover, remove from the heat, and leave for 4 minutes. Lift out with a slotted spoon.
Top each muffin half with bacon and an egg, then spoon over the hollandaise.
