A food cart description:

3. Tokyo Sando

321 SW 2nd Ave
Portland, OR 97204
(971) 254-3744
Visit Website
For this cart’s namesake dish, you’ll get a variety of fillings sandwiched between fluffy slices of shokupan (Japanese milk bread). Owner Taiki Nakajima takes customers on a flavorful journey to his hometown of Tokyo via addictive Japanese-style egg salad sandwiches and other specials, like the decadent Scotch egg sando. Extra-hungry folks can round out their meal with a side of karaage (Japanese fried chicken) or Japanese-style potato salad. Specials rotate weekly, so keep an eye on the cart’s Instagram for the latest offerings. Orders can be placed in advance on their website.

Egg salad or potato salad: sounds like a Kewpie Mayo dream.

I wish we had places like that down here! Mr. SK always misses having japanese milk bread!

We have this:
https://www.tressandwich.com/

Mrs pj says they use milk bread. And Uwajimaya carries some of their sandwiches, too, like the strawberry and cream.