The Elden Ring: Shadow of the Erdtree's Hornsent Grandam quest, or "Horny Grandma" as we (I) have dubbed her at PCG, is definitely a minor character in Elden Ring's beastly expansion pack, but she has a surprising number of interactions available throughout the expansion, and they are somewhat hidden.
Below I've outlined how to find the Hornsent Grandam in the first place, how to first unlock her dialogue and special soup, and when to come back and talk to her again later in your journey through Elden Ring: Shadow of the Erdtree.