I cook for all our D&D games. My latest character is an accidentally cannibalistic monk. Unbeknownst to the other players I've started feeding them recipes based on Hannibal.

My character, through a series of events mostly stemming from a ridiculously low intelligence, is a cannibal monk chef. She even has a magical cookbook gifted to her by her god (her god is a mystery to me, I decided because of her low intelligence she can't pronounce his real name and simply refers to him as Gary, my DM decided her god and only he knows) that has recipes only she can see for how to cook all manner of sentient creatures. She's constantly trying to recruit more followers for her god by getting them to try her cooking.

I (with my DM's sorry support) decided to meta game this to a point such that when it's eventually revealed I'm 100% sure my wife, another player, will be very mad at me but I think it's worth it. I always cook lunch/dinner for our D&D group. Ever since my character found her "unusual tastes" I've only made food from the show Hannibal or, when time or ingredients availability has prevented me from translating a recipe directly from screen to plate, at least inspired by Hannibal. So far I've only been working based on internet recipes I've found but I think I'm going to order the official Hannibal cookbook before the next session.

Weird? Probably. Creepy? Definitely. For now this is a secret just between my DM and I but I might start slowly sharing the secret to other players as their characters decide to partake of my cooking in game.

TL;DR: I'm tiptoeing right up to the line of still technically ethically metagaming cannibalism.

Edit: Just to be clear, in game, the fact that my character is a cannibal is not a secret. She actively harvest pounds and pounds of flesh from our fallen enemies and even threatens them with specific recipes for intimidation checks. The secret of my cooking is purely out of game.