Don’t throw away that tinned fish oil! Use it in this tasty dressing – recipe

Tom Hunt’s potato, caper and red onion salad with tinned fish oil dressing. Photograph: Tom Hunt/The Guardian

Canned fish oil, which we pay for alongside the fish itself, is an absolute flavour bomb that’s not to be wasted. Use the leftover oil for frying a seafood dish such as a kedgeree or when sauteing the base of a fish stew, or turn it into a powerful and flavourful dressing, as in today’s potato salad recipe. I’d recommend using canned fish in extra-virgin olive oil, if you can, but in truth any oil will work. To save energy, boil your eggs on top of the potatoes for six minutes.

Potato salad with tinned fish oil dressing

A simple potato and mayonnaise salad is a wonderful thing. Here, I’ve increased the taste and reduced my waste by using oil from a tin of fish to emulsify the dressing. Of course, this is a dish for fish lovers only. To make the most of my can of fish, I used the fish itself with some pasta the next day, but by all means incorporate it into this salad, if you like.

Serves 4

For the dressing
1 small egg
1 tbsp wholegrain mustard
1 small garlic clove, peeled and finely minced
Finely grated zest and juice of ½ lemon, or 1 tbsp wine vinegar
100-150ml tinned fish oil – top up with extra-virgin olive oil, if need be
Salt and black pepper

For the salad
1kg boiled new potatoes, roughly chopped
1 small red onion, peeled and finely chopped, or 4 spring onions, finely chopped
4 radicchio leaves, optional
40g baby capers
80g gherkins or cornichons, finely chopped
2 hard-boiled eggs, peeled and chopped into large pieces, plus optional quartered or halved boiled eggs to garnish (optional)
6 sprigs soft herbs (eg dill, parsley, mint), plus extra to garnish

To make the dressing, put the egg, mustard, garlic and lemon zest and juice in a small, clean bowl. Whisk in the oil in a slow steady stream, until the mix thickens and emulsifies into a mayo, then season to taste with sea salt and freshly cracked black pepper to taste.

To make the salad, put the potatoes, onion, baby capers, pickles, chopped boiled eggs and herbs

In a large bowl, pour over the dressing and turn to coat and combine. Serve topped with more chopped herbs and some quartered or halved hard-boiled eggs, if you like.

• Discover Tom’s recipes and many more from your favourite cooks in the new Guardian Feast app, with smart features to make everyday cooking easier and more fun. Start your free trial today.