I just found out last week that the stitch I have been using for a while now actually already existed and has a name: the Granito Stitch. It looks a bit similar to the Satin Stitch. You can find out how to make one here, it's really easy! Often the Granito Stitch is used for flower petals, like in the wonderful example in the photo, embroidered by Ana.
I frequently use the Granito Stitch, sometimes in a somewhat rounder form, to embroider eyes on furry creatures instead of using a more bulky French knot. Like here on a White Rabbit.