Seared tuna with ponzu dressing and coriander rice noodles

To make the ponzu, mix half the lime juice, and all of the soy sauce and mirin in a small pan and cook on a low heat until thickened, about 5 minutes. Leave to cool. Brush 1 tsp sesame oil over the tuna steak, season, and scatter over the sesame seeds. Leave at room temperature while you cook the noodles.

Pour a kettleful of boiling water over the noodles and leave to soak for 5 minutes or until tender. Drain and rinse under cold water, leave to drain in a sieve.

Mix ½ tsp sesame oil, the rice vinegar, chilli and remaining lime juice. Toss with the drained noodles and cucumber. Heat a grill pan to hot and sear the tuna for 15-30 seconds on each side, or longer if you like. Leave to rest while you toss the coriander with the noodles. Serve with the tuna and ponzu dressing drizzled over.