Osaka Sushi on Castro serves it, and I've always wanted to make it at home.
I don't know if my recipe resembles the one the chef at Osaka uses, but the outcome was comparable enough that I feel comfortable sharing. The key is to find or make vegan furikake - a spice blend containing seaweed and sesame. We found ours at the market in Japantown. Everything else is simple.
1 cup various mushrooms (I like using several different kinds)
2 tbsp vegetable broth
1 tsp vegan furikake
1/2 tsp salt
a square of foil large enough to hold the mushrooms
Place the mushrooms in the center of the foil square and lightly fold in the corners to create a bit of a bowl. Pour in the vegetable broth, furikake, and salt. Scrunch together the foil corners to close the foil into a pouch. Steam for about 10 minutes if using a pot or about 3 minutes if using an Instant Pot.
It's nice to serve this alongside vegan sushi and a simple greens dish.