Béarnaise sauce (Sauce béarnaise)

1. In a small saucepan, reduce the finely chopped shallot with the white wine vinegar and half of the tarragon stalks by half, then strain (the reduction).

2. Melt the butter over low heat and cool it to lukewarm.

3. In a heatproof bowl, whisk the egg yolks smooth with the lukewarm reduction.

4. Set the bowl over steam and whisk constantly until it thickens to a cream.

5. Off the heat, drizzle in the melted butter in a thin stream until it comes together into a thick emulsion.

6. Stir in the finely chopped fresh tarragon leaves, season with salt and pepper, and serve lukewarm (a classic with steak).

Tip: Béarnaise is the "herby sibling" of hollandaise – the tarragon-and-vinegar reduction gives its characteristic flavour. Stir in the fresh tarragon only at the end to keep its vivid aroma.