Add all of the ingredients to a food processor or high-speed processor and blend until super smooth. Scrape down the sides as you go to ensure the mixture is consistent.
You can use the mixture immediately for a whipped soft consistency. Alternatively, spoon the mixture onto a sheet of parchment paper or cling film. Carefully shape into a log, making sure there are no air bubbles. Then wrap at the ends like a Christmas cracker.You can also scoop it into an airtight container. If doing so, add a layer of clingfilm over the top, touching the surface of the avocado butter - this will help to stop it browning for longer.
Refrigerate for 3 to 4 hours until set and then slice and use.
How To Store
Store the avocado butter covered tightly in the refrigerator and aim to use it within 3-4 days. It will usually last up to a week but will begin to brown before then (it's still okay to use at this point, it's just not as "pretty").You can also freeze the butter. I haven't done this before, but I imagine it would be okay for up to 1-month at-least.
For a dairy-free alternative, you could use olive oil or coconut oil, which harden in the fridge, thus providing the same melty effect as butter. Alternatively, use a vegan margarine/butter instead and adjust the salt accordingly.
Buy ready-to-eat ripe avocados if you plan on making this avocado butter on the same day. Alternatively, buy ripen-at-home avos and wait until they ripen. If you're not ready to use them immediately when ripened, place them in the fridge to slow down the ripening process but try to use them in the next day or two to avoid too much browning or it becoming overripe.
If you don't have a food processor, then you can mash this avocado butter by hand. It won't have quite the same whipped consistency but will work.