Tiger prawn skin with sea vegetable and citrus dashi

1.For citrus and mushroom dashi, place shiitake and kombu in separate containers each with 500ml water, cover and set aside overnight at room temperature. The next day, heat kombu and its water to 60C in a saucepan and hold temperature for 1 hour. Add shiitake and their water to kombu, heat mixture to 85C, then add bonito flakes. Remove from heat, cover and stand for 5 minutes, then pass stock through filter paper placed in a conical sieve, changing filter papers as needed (discard solids). Season with soy sauce, mirin and ponzu vinegar and keep warm. Add lemon rind just before serving.

2.Shell prawns and remove heads. Place a prawn on a board leg-side up and cut down belly with a sharp knife from head to tail until you reach the intestinal tract. Remove tract and discard. The prawn should look like it has been butterflied open. Score prawn, then place in a vacuum bag. Seal to a 165mm x 165mm square on full vacuum. Using a meat tenderiser or rolling pin, firmly flatten the prawn on flesh side only. Do not flatten the skin side, or it will break the tiger prawn pattern. Use a rolling pin to roll the prawn meat into the entire bag, ensuring meat is pushed evenly into the corners. This is important; otherwise the sheet will not be thin enough. Repeat with the remaining prawns and bags.

3.Preheat a steamer to 63C. Place prawn sheets in a single layer on a steamer tray and steam until just cooked (5 minutes). Or bring a large saucepan of water to 63C and add prawn sheets and cook gently until just cooked (3-4 minutes). Cut all 4 sides of the vacuum bags and remove the prawn sheets, and place each in the base of a serving bowl. Scatter sea vegetables on and around the prawn skins. Pour citrus and mushroom dashi over prawn skins and finish with a pinch of nori powder. Serve immediately.