In a high-speed blender or the bowl of a food processor, process 120 grams (1 cup) of fresh or thawed frozen raspberries until smooth:

Pass the purée through a fine mesh strainer to remove the seeds, periodically scraping the bottom of the strainer with a rubber spatula or bench scraper to remove the purée that collects there.

Re-weigh the purèe to 60 grams, or about 1/4 cup.

In a small saucepan, warm whipping cream and raspberry purée over low heat until steaming. Do not boil.

Meanwhile, melt the ruby chocolate over a bain marie or double boiler.

Whisk the warm raspberry cream into the melted chocolate, followed by the butter.

Set aside and allow to rest, uncovered, at room temperature until ready to use.

To use, whisk briskly until thick, smooth, and creamy.*

Use as desired.

Store leftover ruby ganache in an airtight container in the refrigerator for up to 1 week.