Melt butter in the microwave or on the stove-top until very hot.
Toast English muffin halves.
Heat slices of Canadian bacon in microwave or on the stovetop.
In a small saucepan, over medium heat, whisk egg yolks, lemon juice, mustard, salt and cayenne pepper until combined.
Stirring continuously, slowly pour hot butter into this mixture; thin with water, if needed.
Plate the English muffin halves, each topped with a slice of Canadian bacon and a poached egg.
Spoon hollandaise sauce over eggs.
