Step 1

1. Put a medium-sized saucepan on a high heat, add the oil, onion, chilli and garlic and cook until soft. Add the tomatoes and cook until soft, completely broken down and caramelised.

Step 2

2. Add the vinegar and lemon juice, cook for a few more minutes then turn the heat down to low. Constantly swirling the pan, add a few pieces of butter at a time. Once they have melted, add more butter until all the butter is used. Do not overheat or overwork the beurre blanc or it will split.

Step 3

3. Remove from heat, add the herbs, season well and serve with our delicious fish cakes.