Set the butter in a small saucepan over heat and melt it, then whisk the egg yolks in a separate bowl with the lemon or lime juice, heavy whipping cream, and salt and pepper. The yolk mixture should look smooth and slightly thick before any hot butter goes in.

Drizzle in a small spoonful of the hot butter while whisking, then keep adding the butter a little at a time until the yolks are warmed and loosened. This tempering step protects the eggs, and the mixture should stay glossy rather than turning grainy.

Pour the tempered mixture back into the saucepan and cook briefly, stirring just until it thickens. The hollandaise is ready when it coats the back of a spoon, like warm mayonnaise.

Pour about 3 inches of water into a pot, bring it to a boil, then lower the heat until you see a gentle simmer and add a splash of vinegar. Look for small bubbles coming to the surface, not big bursts of boiling water.

Crack one egg into a small cup, then slide it gently into the simmering water and cook it for 3 to 5 minutes depending on how soft you want the yolk. The white should set around the yolk and feel firm on the outside while the center stays soft.

Lift the egg out with a slotted spoon and repeat with the remaining eggs. A finished poached egg should feel delicate but hold together cleanly without ragged strands everywhere.

Toast the English muffins and warm the Canadian bacon. The muffins should be golden and crisp enough to stay sturdy under the sauce.

Place one slice of Canadian bacon on each English muffin half, then set a poached egg on top. Keep the stack centered so the egg sits securely and the yolk stays intact.

Spoon the hollandaise over each egg and serve right away. The sauce should drape over the egg in a thick, glossy layer without running off like water.