1 Tbsp coriander seeds
1 Tbsp fennel seeds
500g rock salt
zest of 2 lemons, finely grated on a microplane
4 portions tuna belly (100g each)
1 white onion
1 Tbsp olive oil
1 whole fennel bulb
freshly ground black pepper
Toast the coriander and fennel seeds in a hot, dry pan until fragrant. Remove from the heat. Set aside half a teaspoon of the toasted seeds to use as garnish. Combine the remaining seeds with the salt and lemon zest and mix well.
Preheat the teppanyaki grill on the Furnace BBQ.
Sprinkle half the salt mix along the back of the teppanyaki grill to make a salt bed approximately 1cm deep. Allow the temperature of the salt bed to reach 70°C and lay the pieces of tuna belly on top leaving a small gap in between each piece. Sprinkle the remaining salt mix on top, covering the tuna pieces completely. Leave to cook for 12 minutes. Check the temperature of the centre of the tuna belly by using a probe thermometer. Once the core reads 45°C, remove the pieces from the salt, and brush off all visible salt and seeds. Season the tuna with a generous squeeze of lemon and garnish with the toasted seeds.
While the tuna is cooking, peel and slice the onion 2mm thick without separating the rings. Drizzle half the olive oil onto the front part of the teppanyaki grill and lay the onion slices on the grill, cooking until golden and caramelised. Remove and season with salt. Carefully shave the fennel using a mandolin 2mm thick and place in a bowl. Drizzle over the remaining olive oil and season with salt. Lay the fennel slices on the teppanyaki grill and cook until tender. Remove and add to the onions, seasoning with some lemon juice and freshly ground black pepper. Serve the grilled fennel and onion with the tuna.