Insert simmering basket, weigh in 500 g rice, remove simmering basket, with the aid of the spatula and rinse rice until water runs clear.

Leave simmering basket in position for a couple of minutes to drain, and remove with aid of spatula. Transfer steamed rice to a large non-metal shallow dish and sprinkle vinegar caramel all over, saving 3-4 tablespoons of caramel vinegar, for assembly. Using spatula, toss gently to distribute vinegar caramel. Discard steaming water.

Wrap a bamboo sushi mat in cling film. Place a sheet of nori, shiny side down on bamboo sushi mat. Wet your hands or use some mayonnaise to keep rice from sticking to them. Place a plate on mixing bowl lid and weigh in 120-150 g rice. Shape rice into a tennis bowl. Repeat until you get 6 rice balls.

Place one rice ball over nori sheet, with wet hands leaving clear 1 cm around.

Sprinkle rice with white toasted sesame and black sesame seeds, then, very carefully, flip nori sheet over so that it is rice side down on mat.

Αt the end of nori sheet closest to you, spread some mayonnaise in a line 1 cm from the edge. Lay smoked salmon along mayonnaise, then lay a line of cucumber, deseeded, cut in matchsticks 3-4 mm and avocado besides cucumber, using a pastry brush, brush the top end of the roll with the reserved caramel vinegar. Using bamboo sushi mat, begin rolling tightly to form a roll. Repeat procedure until you get 6 rolls.

Using a wet, sharp knife, slice each roll into 8 pieces.

Serve immediately with soy sauce, pickled ginger, wasabi paste and mayonnaise.