For the tarragon vinegar:

200ml white wine vinegar
Pinch of black peppercorns
Half a bunch of tarragon

For the sauce:

150g butter
3 egg yolks, keep the whites for meringues or chocolate mousse, don’t waste anything
1⁄2 tsp tarragon vinegar
Lemon juice to taste
Salt and pepper to taste

For the tarragon vinegar:

1. To make the tarragon vinegar, bring 200ml of white wine vinegar to the boil. Add a pinch of black peppercorns and half a bunch of tarragon, and leave to cool.
2. Strain through a sieve and that’s it – there you have tarragon vinegar. Store in a kilner jar in the fridge, it will make your Hollandaise sauce taste fantastic.

For the sauce:

1. Melt the butter in a saucepan and set aside.
2. Put the egg yolks, 1⁄2 tsp tarragon vinegar, a pinch of salt and a splash of water in a bowl that will fit over a small pan.
3. Whisk for a few minutes, then put the bowl over a pan of barely simmering water and whisk continuously until pale and thick, about 3-5 minutes.
4. Remove from the heat and slowly whisk in the melted butter, bit by bit until it’s all incorporated and you have a creamy hollandaise.
5. If it gets too thick, add a splash of water.
6. Season with salt and pepper and a squeeze of lemon juice.
7. Keep warm until needed.