Light and fresh, these tuna rolls balance tangy, sour and sweet flavours for a delicious meal that’s super-quick and barely requires any cooking at all. Ideal for dinner or lunch, you could serve with a handful of potato crisps on the side.
Finely chop celery and red onion. Drain tuna.
Roughly chop capers. Thoroughly wash coriander and finely chop leaves and stems. Zest and juice lemon, set aside half the zest and juice. Place remaining zest and juice in a bowl with capers, coriander, mayonnaise, Dijon mustard, 1⁄2 teaspoon sea salt and a good pinch of black pepper and stir to combine.
Thinly slice spring onions. Heat 20ml (1 tablespoon) olive oil in a frypan over medium heat. Add spring onion and cook, stirring occasionally, for 6–7 minutes or until golden and caramelised. Transfer to a bowl and wipe out the pan.
Place remaining oil, remaining lemon juice and zest and spring onion in a large bowl with 1⁄4 teaspoon salt. Add rocket leaves and toss to coat.
Place tuna, caper mayo, celery and red onion in a bowl, season to taste and mix to combine.
Halve burger buns and toast, cut-side down, in frypan for 1 minute. Divide tuna mixture between buns and top with half the rocket salad. Serve immediately with remaining salad on the side.