http://www.bbc.co.uk/food/recipes/barnaise_sauce_89217
Ingredients
- 300g butter
- 4 tbsp white wine vinegar
- 1 tbsp sherry
- 4 shallots, chopped
- 3 tbsp chopped fresh tarragon, plus 2 tbsp whole tarragon leaves
- salt and freshly ground black pepper
- 4 free-range egg yolks
- 1 tsp lemon juice