Mince the onion and microwave it for 1 minute at 600W. Let it cool. Peel and grate the daikon, then squeeze out excess water. Trim the stems off the shiso leaves.

In a bowl, mix okara powder and milk. Add ground meat, onion, egg, salt, and pepper. Mix thoroughly until the meat becomes sticky.

Divide the meat mixture into two portions. Shape each into an oval patty, pressing to remove air and creating a slight indentation in the center. Chill in the refrigerator for 10 minutes.

Heat vegetable oil in a frying pan over medium heat. Cook the patties for 2 minutes on one side until browned. Flip, cover, and cook on low heat for 4 minutes until fully cooked.