Recipe from the UK Thermomix Website
Very similar to hollandaise with the addition of tarragon and black pepper. Great accompaniment to most meats and vegetables.
Few sprigs tarragon
1 spring onion/shallot
½ tsp peppercorns
2 tbsp white wine vinegar
2 tbsp white wine
3 egg yolks
Salt and pepper to taste
150g unsalted butter
Place tarragon into TM bowl and chop for 5 seconds on speed 6. Set aside.
Place spring onion/shallot and peppercorns into TM bowl and chop for 6 seconds on speed 8.
Add remaining ingredients (including tarragon) and cook for 6 minutes at 80ºC on speed 4.
Should your sauce separate, (this can depend on the freshness of your eggs) simply increase to speed 10 for 20-25 seconds whilst you add 1 tbsp boiling water through hole in lid. To thin sauce, add 1-2 tbsp boiling water, to thicken, 1-2 tbsp additional butter.