Make a few small cuts around the edges of each pork steak so they will cook without shrinking.Place the meat in between two plastic wrapper and use a meat pounder or back of knife to flatten them. Take care not to break the meat. Season each piece with salt and pepper
Cover each pieces of meat in flour, shake off any excess and then dip in beaten egg and coat with breadcrumbs
Preheat about 1/2 cup of oil in a large pan or skillet. Pan fry each piece of met on medium to high heat until they are cooked through and golden brown. When cooked, drain on a rack or some paper towels to remove and excess oil. When they are cool enough to handle, dice them into bite-size. Mix the chicken with kewpie mayo. Set aside
Assembling:
Slice the avocado thinly. Scoop about 1 Tbsp of the meat mayo mixture and place on a clean plate/chopping board and roughly shape it into a ball with a help of spoon or your clean fingers (don't have to be exactly round). Place about 6-7 slices of the avocado on top of the meat. Place the plastic wrap on top and wrap it up and it will help you to shape it into round balls (refer to the short clip below)
Garnish with some fish roe (optional). Best served on the same day, as the avocado may gradually turn black if left for too long. They can be served cold or room temperature. Repeat with the rest of the meat and avocado
Notes
You can substitute pork with boneless skinless chicken thighs (I'm not a chicken breast person, but feel free to use it if you prefer). Or just use sushi rice if you prefer meatless version