2 fresh tuna steaks 1.5 cm–2 cm thick (each about 240g)

A handful of coriander leaves chopped (10g)

1 red chilli deseeded and finely sliced

1 shallot finely sliced

Grated zest and juice of 1 lime

1 clove garlic crushed

1 lemongrass stalk bruised and finely chopped

1 tbsp kecap manis (Indonesian-style sweet soy sauce available in large supermarkets or Asian grocery stories) (use a gluten-free alternative if following a gluten-free diet)

1 tbsp olive oil

½ ripe avocado stoned peeled and diced

4 spring onions thinly sliced

Grated zest and juice of ½ lime

2–3 red and yellow cherry tomatoes deseeded and chopped

10g fresh coriander roughly chopped

1 tsp black and white sesame seeds toasted (optional)

½ lime cut into wedges (optional)