What is Tonburi?

In Season 19 of Great British Menu, Scott wanted to use Tonburi in his vegan starter in place of caviar.

Tonburi, also known as "land caviar" or "vegan caviar", is the dried, peeled outer skin of the summer cypress, Kochia Scoparia, which is native to Japan. The seed is green, 1–2 mm in size, and has a texture similar to fish roe. The seeds are harvested and then dried before being boiled and soaked in cold water for about 24 hours. 

Tonburi offers a unique texture and umami-rich flavor.

In the end, Scott's tonburi didn't arrive in time for him to incorporate it as he wanted. He used a ponzo and yuzu gel instead.