Finely chop the jalapenos, grate the garlic and zest the lime.
Add to a bowl with softened butter.
Squeeze the juice of half a lime into it. Give it a mix.
Transfer to a cling wrap or parchment paper.
Roll the cling wrap to shape the jalapeno butter in a log. Refrigerate for an hour or more and use.
Notes
If your taste buds are sensitive to heat, you can remove the seeds and white membrane from the center of the jalapenos and use only the green part.
You can also add some finely chopped parsley or dill (or both) to the mix to make it more herby and delicious.
If you're using unsalted butter, you may want to add a bit of salt to season the butter.
If you don't like the chunky bits of jalapenos in the butter, you can blend the garlic and jalapenos together in a blender jar to make a smooth paste, and then fold the mixture into the butter