Just found this recipe - I can't eat pork for medical reasons. What cut of beef could be subbed for the ground pork?

A mix of ground chicken and shrimp would be nice, too.

Thanks so much! Lamb def sounds interesting

You could use any cut of beef that's not too lean. My Japanese friend uses just regular ground beef (or sometimes even lean ground beef, but I find those a bit dry). Sometimes she will skip the meat all together and use a combination of mushrooms and tofu.

When I make something like this (planing to grind my own meat) I usually choose my beef by price and marbling more than by specific cut.

Have you considered lamb for this recipe? Not the most traditional (except in a few places like Northern Japan) but surprisingly yummy!