Hito no Shokuji wa Muzukashii.

Hashimoto, a vampire who has survived for 260 years by consuming a milk substitute for blood, stumbles upon a manga about gourmet food and becomes curious about human cuisine. He begins experimenting with various dishes, which should be a delightful experience—except he is a reclusive, long-lived being with little understanding of modern human society. His lack of familiarity with how things function in the present day leads to complications, making his culinary adventures anything but straightforward.