First make the Hollandaise sauce.
Put the lemon juice and vinegar in a
small bowl, add the egg yolks and whisk
with a balloon whisk until light and frothy.
Place the bowl over a pan of simmering
water and whisk until mixture thickens.
Gradually add the butter, whisking
constantly until thick – if it looks like it
might be splitting, then whisk off the heat
for a few mins. Season and keep warm.
To poach the eggs, bring a large pan
of water to the boil and add the vinegar.
Lower the heat so that the water is
simmering gently. Stir the water so you
have a slight whirlpool, then slide in the
eggs one by one. Cook each for about
4 mins, then remove with a slotted spoon.
Lightly toast and butter the muffins,
then put a couple of slices of salmon on
each half. Top each with an egg, spoon
over some Hollandaise and garnish with