Filbert Butter This page first published: Jan 25, 2006 · Updated: Jun 23, 2018 · by CooksInfo. Copyright © 2021 · This post may contain affiliate links · This blog generates income via ads · Filbert Butter is 1 part filberts, ground to a paste, combined with two parts butter. The mixture is then forced through a sieve. Filbert Butter is used as a garnish on hors d’oeuvres, soups and sauces.