Mustardy Mackerel, Spinach and Spuds

I seem to major on smoked mackerel and potato salads, this one is a little bit different with lots of mustard and spinach instead of salad leaves. It was delicious and I'm really starting to like raw spinach as a salad. This recipe comes from River Cottage Light and Easy.

Mustardy Mackerel, Spinach and Spuds
(River Cottage Light and Easy - Hugh Fearnley-Whittingstall)
(Serves 4)

800g new potatoes, cut into bite sized chunks
150g baby leaf spinach
3 medium smoked mackerel fillets
1 lemon
salt and pepper

For the dressing
3 tbsp extra virgin olive oil
1 tbsp cider vinegar
1 tsp smooth mustard
1 tsp grainy mustard
scrap of garlic, crushed

Put the potatoes in a saucepan, cover with water, bring to the boil. reduce the heat and simmer for 7-10 mins, until just tender.

Put the dressing ingredients into a jar, add a pinach of salt and some pepper and shake to emulsify.

When the potatoes are cooked, drain them well and return to the hot pan.

Flake the smoked mackerel.

Put the spinach into a lunch box and top with the potatoes and mackerel. Squeeze over the lemon juice and add the dressing, toss well and serve.