300 gram piece tuna
½ cup finely chopped fresh herbs eg, flat-leaf parsley, coriander and chives
sea salt and freshly ground pepper
1 tablespoon dry mustard powder
2 teaspoons cold water
2 tablespoons grated fresh ginger
1 tablespoon grain mustard
2 tablespoons rice vinegar
2 tablespoons soy sauce
2 tablespoons vegetable oil
1-2 teaspoons honey
2 tablespoons pickled ginger, thinly sliced
1 teaspoon black sesame seeds, toasted
small rocket or other salad leaves
Tuna: Brush the tuna with olive oil and season with salt and freshly ground pepper. Spread the herbs on a chopping board and roll the tuna in the herbs to coat on all sides, pressing it on firmly to adhere.
Heat a heavy-based sauté pan with a little olive oil and sear the tuna for 30 seconds on each side. Carefully transfer to a plate and rest for 5 minutes.
Lay a large piece of plastic wrap on the bench and place the tuna on one end. Roll up tightly then twist the ends like a Christmas cracker. Holding the ends continue to roll the tuna until it forms into a nice tight salami shape. Refrigerate until ready to use or for at least 2 hours.
Drizzle: Put the dry mustard in a bowl and stir in the cold water to make a smooth paste. Place the grated ginger in a small piece of muslin and squeeze the juice onto the mustard. Discard the grated ginger. Whisk in the grain mustard, rice vinegar, soy and the vegetable oil. Add honey to taste. Leave the dressing for a few hours or overnight for the flavors to mellow.
To serve: Unwrap the tuna and use a sharp knife to cut ½ cm thick slices.
Arrange on a serving platter and drizzle over a little of the dressing. Scatter the pickled ginger, sesame seeds and the salad leaves over the tuna. Serve immediately.