Sushi Rice:

For the seasoning, heat rice vinegar with sugar and salt in a stove pot or microwave. Mix until fully dissolved. Cook sushi rice with water in a thick bottom pot (or rice cooker). Once ready, transfer rice to wooden or plastic container. Do not cover. Pour seasoning evenly over rice and mix with wooden spoon in a cutting motion.Let rice cool down to room temperature by the window, but never in the refrigerator. Mix through black sesame seeds.
 

To Assemble:

Ensure beef mixture does not have to much fluid, you can strain the fluid out if needed. Using two forks pull the beef so it is shredded and will be easy to spread.

Line an 8-inch springform pan with plastic wrap. Fill the pan with a third of the cooked rice. Use a piece of wax paper or potato masher to press it down into a compacted flat layer. Tear nori into smaller pieces (this makes it easier to cut the cake than if it is one whole sheet. Arrange sheets to cover the layer of rice. You should use about 1 sheet per layer. 

Spread the pulled beef mixture across to cover the seaweed and gently press down with potato masher. Repeat rice layer with another third of the rice, followed by another seaweed layer using nori seaweed pieces. Next spread the avocado to cover the seaweed. Repeat with the final layer with the remaining rice.

Remove the springform pan by popping open and removing plastic wrap carefully. The cake will keep at room temperature for a few hours before serving. Do no refrigerate as this dries out the rice.

Just before serving garnish with sliced cucumber and pickled ginger. We like to cut small pieces of seaweed for garnishing on-top.

Slice and serve with soy sauce and wasabi. Complete the meal with steamed seasonal greens alongside.