The classic buttery sauce for fish.

The beurre blanc is an emulsion of half-salted butter and a reduction of white wine, vinegar and shallots. This classic sauce pairs beautifully with salmon, tuna or white fish.

INGREDIENTS

• 250 g (1.1 cups) of plain or salted butter

• 50 g (3.3 tbsp) of shallot finely diced (grey jersey shallots are best)

• 50 ml (3.5 tbsp) of dry white wine (Muscadet wine is best if you can find some, otherwise any french dry white white such as Anjou, saumur or burgundy white will do. You can also use dry white vermouth instead of wine)

• 25 ml ( 1.7 tbsp) of good quality white wine vinegar

• Salt and cayenne pepper to taste (if you use salted butter you don't need to add any salt)

NOTES

• They main challenge with this recipe is maintaining the temperature under 50 °C when making the sauce. Follow the technique in the recipe below and in the video to help with this.

• The beurre blanc is a base sauce for fish and it can be enhanced by adding a good quality fish stock, fresh herbs, spices or pureed vegetables.

• If you leave the sauce to cool down too long it will start to thicken into what looks like a yellow buttery paste. If this happens, don't panic. Just add one or two tablespoons of hot water or fish stock and whisk well over low heat. That renowned whitish color and shine should return to the sauce.

PROCEDURE

1. Start by preparing and weighing the ingredients. Peel and finely dice the shallots, measure the white wine, white vinegar and cut the butter in small pieces.

2. In a thick bottom pan over low heat, start by melting a small piece of butter.

3. When the butter has melted and foaming add the shallots and leave to "sweat" for a minute until the shallots are translucent.

4. Add the white wine and vinegar and leave to reduce until you are left with a tablespoon of liquid.

5. Turn the heat off and add 2 or 3 pieces of butter one at a time while stirring gently with a whisk until the butter starts to melt. When the first pieces of butter have melted, whisk more vigorously and add more butter continuing to whisk.

6. Now turn the heat back to low and repeat the process of adding more butter and whisking. Ensure the temperature of the sauce does not exceed 65 °C (150 °F) to avoid the sauce failing. I turn the heat off periodically and check the temperature of the bottom of the pan lightly with a bare hand. I find that maintaining the sauce at 50 °C (122 °F) works well which is what your hand can bare. If it’s too hot to touch this means the temperature is too high and you need to turn the heat off again, while continuing to whisk. Of course you can use a cooking thermometer or a double boiler.

7. When all the butter has been incorporated, the mixture should be a thick pale yellow sauce.

8. Season the sauce with salt (if you haven’t used salted butter) and a pinch of cayenne pepper.

9. Finally, pass the sauce through a sieve (chinois) pressing the cooked shallots down to add extra taste to the sauce.

10. When the sauce is filtered, use it immediately. It’s most delicious with poached fish.