@morning-softness reblogged my Caleb bio post with these tags, and I'm so glad you asked! The short answer is, Caleb's vampirism created his attitude towards cooking.
The long answer is that SDverse is urban fantasy, not horror, so vampires are a fantasy sophont species rather than always-antagonistic monsters. They're just folks! And sure, you have your Count Draculas and your Henry VIIIs who see humans as livestock to be subjugated and fed upon, but that has more to do with them being royalty than them being vampires. Vampires can subsist comfortably on a liter of blood every few weeks, far less than it would take to kill someone; it takes a lot of gorging to get to the level of power and indestructibility of Count Dracula, and as Count Dracula proves, that gets you noticed, and all it takes is a handful determined best friends to slap you back down. There's a reason the world hasn't been taken over by bloodthirsty overlords; most vampires just don't want to.
So your average ham-and-egger vampire isn't going to have the power, resources, and preexisting authority and mystique to get away with terrorizing the local populace. If they're discovered, they're more likely to have people charging out with torches and pitchforks than cowering in their homes. So, they have about two options. Either they get really good at stealth, never stay in one place long enough to be noticed and, most importantly, don't get greedy when they feed. Or, they can deal openly, and fairly, with the humans they feed on.
It's not uncommon for vampire clans to have permanent or semi-permanent human entourages, who trade their blood for protection, monetary payment, or whatever goods and services the vampires can provide. These arrangements can be exploitative, of course, but most vampires who take this route know that what you put into it is what you get out of it. A vampire that takes good care of their humans is a well-fed vampire.
Caleb's clan had a number of human members over the years, two of whom ended up turning and joining the clan permanently. As a human, Caleb had learned to cook out of necessity, both to directly feed himself and as a skill he could be paid for. As a vampire, he took it up again, got very good at it, and found a lot of joy in feeding his humans healthy (iron-rich, of course) meals. As the centuries passed, he was always on the lookout for new cookbooks, and new advances in medicine and nutrition. Gotta keep those humans happy and healthy, so they can keep you happy and healthy, too.
He hasn't cooked in a while.