For the marinade, mix together all the ingredients in a bowl. Set aside.
Trim the beef fillet of any fat or sinew and cut it into wafer-thin slices using a sharp knife.
Add the beef slices to the marinade bowl and mix them around with your fingertips to make sure they are completely coated. Add the pear and mix together.
Place a large cookie cutter or chef’s ring onto the center of a plate. Spoon the beef mixture into the cutter or ring, pressing down on the edges. Carefully place the egg yolk in the middle.
Remove the cutter or ring and serve scattered with the sesame seeds and scallion slices.
