Watercress tzatziki and mackerel shells with aromatic herbs and spicy hazelnut oil

3 tbsp olive oil

1 tbsp pul biber, gochugaru or other mild chilli flakes

30g (1oz) toasted hazelnuts, roughly chopped

350g (12oz) conchiglie (shells) or orecchiette

2 or 3 smoked mackerel fillets, for flaking

Lamb’s lettuce, to serve (optional)

For the watercress tzatziki:

100g (3 ½ oz) hot, peppery watercress

300g (10 ½ oz) thick Greek yoghurt

1 tsp flaky sea salt, plus extra to taste if needed

15g (½ oz) flat-leaf parsley, plus extra to serve

10g (½ oz) dill leaves, plus extra to serve

10g (½ oz) mint leaves, plus extra to serve

100g (3 ½ oz) olive oil

Zest of ½ lemon + 1 tbsp juice

1 tbsp rice vinegar or white wine vinegar

1 small garlic clove, grated

2 spring onions (scallions), trimmed and roughly chopped

Method

• Begin by making the tzatziki. Wash the watercress and place in a colander. Add the flaky salt and scrunch the leaves, then leave to sit for 20 minutes before squeezing to extract as much moisture as possible. Place the squeezed watercress in the bowl of a food processor, along with the remaining tzatziki ingredients, and process until smooth. Check for salt (it might need a little more, depending on how salty the watercress was). It should taste peppery, bright and fresh.
• Heat the olive oil with the pul biber in a small pan over a low–medium heat and cook gently for a few minutes until the oil is crimson. Add the hazelnuts and a small pinch of salt, then remove from the heat and set aside to cool.
• Cook the pasta in plenty of salty water until tender (the maximum time on the packet instructions) then drain.
• Rinse the pasta under cold running water until cool, then transfer to a mixing bowl.
• Combine with the tzatziki, loosening with a little cold water if you think it needs it.
• Transfer to individual serving plates, then flake over the mackerel and finish with the spicy nut oil, scattering over a few more herbs. Serve with (simply dressed) lamb’s lettuce, if you like.

Recipe extracted from Cool Pasta (Hardie Grant)