Start by combining the pesto and the softened butter in a bowl.
Mix it together using a spoon or a fork until you get a consistent mixture.
Transfer it on a sheet of cling wrap and roll it into a log. Refrigerate or freeze for a few hours and then use as needed.
Notes
It is always a good idea to use freshly prepared pesto for this recipe. This will ensure that the pesto butter has that bright green color you’re looking for.
I like to use a simple bowl and a fork to combine all the ingredients together, but if you are making this in a big batch, you can use a food processor to give it all a good mix.
Remember to add some lemon juice while making pesto. This will help preserve its bright green color.