*note: Leave butter out for several hours until soft. This is very important. If you use cold butter, it won’t work.
Put Uni eggs in a bowl, and with an electric mixer, whip the eggs until they are smooth and velvety in consistency, similar to pancake batter. Set Aside. In a Large electric mixer, add the softened butter, and start mixing on the lowest setting. Slowly add the Uni mixture until its completely blended with the butter. Once it is blended, turn up the speed on the mixer to medium.
Add in lemon juice, salt, pepper, chives, and cayenne. When it is needed, scrape down the sides of the bowl with a rubber spatula. Continue mixing for 2-3 minutes until everything is well blended into a smooth, creamy consistency.
On a flat surface, lay down a good size sheet of wax paper. Place the Uni butter on the wax paper, and roll it into a log about 2 inches in diameter. Fold over the ends of the wax paper and roll it to seal.
Place the log in the refridgerator for a couple of hours to firm up. When firm, you can cut the butter into smaller pieces and keep it in fridge for a few days, or freeze the extra butter if you want to save it for another recipe in the future.