In the bowl of a mixer fitted with a paddle attachment, combine the Uni, softened butter and yuzu juice. Mix until completely incorporated, scraping down the mixer as needed. Place in a vessel coved with plastic wrap so not to form a skin.
Roughly chop the herbs and combine them in a bowl. Add remaining ingredients and mix together, season with salt and set aside, can be made 24 hours.
Slice brioche, toast until golden in a 325 degree oven, on a sheet tray lined with a rack.
To serve temper uni butter, spread on toast and with the salsa verde on the side.