Rosti fish cakes

• potato↗300g g
• can tuna↗80g g

  in brine, drained (or use salmon - see tip, below)

• caper↗2 tbsp tbsp

  in brine, drained

• spring onions↗2

  trimmed and finely chopped

• large egg↗1

  beaten

• olive oil↗4 tbsp tbsp
• bunch asparagus spears↗½

  from Asparagus, pea & feta frittata - see 'goes well with')

• lemon juice↗1 tbsp tbsp
• Dijon mustard↗1 tsp tsp
• pack watercress↗½

Step-by-step instructions

1. 1

   Thickly grate the potatoes onto a plate, then squeeze handfuls of it to remove any excess liquid. Put it in a large bowl, then add the tuna, capers, spring onion and beaten egg, and season well with ground black pepper.

2. 2

   Heat half the olive oil in a large frying pan. Divide the potato mixture into 4 and spoon into the pan in mounds, gently pressing down with the back of a spoon. You may have to do this in batches. Cook for 7-10 mins, turning once, until crisp and golden.

3. 3

   Meanwhile, put the asparagus in a frying pan and cover with boiling water from the kettle. Bring to the boil and cook for 3 mins or until the asparagus is just tender, then drain. Mix the remaining oil with the lemon juice and mustard and season well. Put the watercress in a bowl and drizzle over the oil and lemon juice mixture. Toss well. Serve the fish cakes with the asparagus and watercress.