Homemade cold bearnaise sauce

Homemade cold bearnaise sauce. Absolutely delicious and actually really simple, this batch is enough for about 8 people, so reduce it if you don't want so much or increase if you want more.

200g butter

1 1/2 tbsp dried tarragon

1 tbsp white wine vinegar

4 egg yolks

2 dl rapeseed oil

Salt

White pepper

Do this:

Melt the butter in a saucepan and let it cool until it is room temperature.

Mix the tarragon and vinegar together in a small bowl and let it stand for a while, I usually crumble the tarragon a little for extra flavor, I love tarragon. Stir to mix everything.

Beat the egg yolks in a tall, narrow bowl, preferably with an electric whisk, and add the oil in a fine stream (use the same temperature for eggs and oil, I had refrigerator-cold) when it starts to thicken, you can add in a thicker stream, beat until you have a thick and glossy cream.

Beat in the butter (not the white that remains at the bottom), a little at a time and finally add the vinegar and tarragon mixture. Season with salt and pepper.

Keep cold until serving.