Toast 2 English muffins
Cook 4 slices Canadian bacon or ham in a skillet until warmed through
Fill a saucepan with 2 inches of water and bring to a gentle simmer
Add 1 tablespoon vinegar to the water
Crack 4 eggs into separate small cups
Stir the water to create a gentle whirlpool
Slide each egg into the water and poach for 3 to 4 minutes
Remove the eggs with a slotted spoon and drain on paper towels
Whisk 3 egg yolks, 1 tablespoon lemon juice, and a pinch of salt in a heatproof bowl
Set the bowl over barely simmering water and whisk until slightly thickened
Slowly whisk in 1/2 cup melted butter until the sauce is smooth
Add a little warm water if needed to thin the sauce
Place the toasted muffins on plates
Top each muffin half with Canadian bacon or ham
Place a poached egg on top of each
Spoon hollandaise sauce over the eggs
Serve immediately