1. Bring a large pot of water to a vigorous rolling boil. Add half a lemon to the water. Add the lobster tails and cook for 6-12 minutes or until the shells turn bright red and the meat is tender when poked with a fork. 

2. Place a frying pan over medium heat. Add the butter and once melted and sizzling, add the yuzu and briefly add the lobster tails, flesh side down, and cook for 30-45 seconds or until the meat lightly chars. Using a fork, pull the meat from the shell and allow to cool until you can comfortably handle it. Chop the meat into bite-sized pieces. 

3. Combine the mayonnaise, lemon zest, yuzu juice, yuzu koshu and chives in a medium bowl. Season generously with salt and pepper. Add the chopped lobster meat and stir to generously coat. 

4. Return the frying pan to the heat and quickly add the brioche roll halves, cut side down, and cook them in the residual butter and yuzu mixture until lightly toasted.

5. To assemble, scoop on some of the lobster mixture onto a brioche half, top with some potato crisps, and sandwich with the top brioche half. 

Repeat with remaining lobster mixture and brioche rolls. 

*Everything you need to know about yuzu (including stockists)

Tip: if you aren't confident cooking the lobster, you can purchase precooked lobster meat from a fishmonger.