Method

To make the Hollandaise sauce, place the white wine vinegar, black peppercorns and tarragon sprigs (if using) in a small saucepan. Bring to the boil and reduce down by around half. Strain the vinegar into a jug.
Place the butter in a saucepan and melt until the butter has separated and the solids are at the bottom of the pan. Skim off any residue from the top with a spoon.
Place a small saucepan half filled with water on a low heat with a heat proof bowl securely on top. Add the yolks to the bowl with vinegar and whisk well. Still whisking all the time very slowly drip the lovely yellow liquid butter into the warming bowl until you have a lovely bright, smooth Hollandaise sauce. This will take a little while but keep going. Add a little lemon juice and keep the bowl on top of the pan of water to keep warm whilst you poach the eggs. Whisk the sauce occasionally to stop it from splitting then turn off the heat.
Place a large saucepan of water on a medium heat. Poach the eggs to your liking by simply cracking them into the slowly bubbling water and letting them bob around for 3-4 mins until cooked then fish them out with a slotted spoon.
Halve and toast the muffins then butter them. Divide the muffins between the plates. Top with fresh spinach leaves, salmon and a poached egg. Spoon over the silky Hollandaise sauce, sprinkle over some chopped chives and serve with a little lemon wedge.