How to Make It
Pour oil into the Instant Pot, layer the pork belly on top and push the saute button. Stir pork periodically so it does not stick to the pot as the fat renders out. Once the meat and fat are mostly browned and translucent, stir in the shallots, and keep them moving until they have softened. Pour in about 1/2 cup of broth and stir to remove any stuck-on bits from the bottom of the pot. Hit the cancel button to end the saute function.
Using a sharp knife, pierce the skin of the turkey leg all over to allow the juices to run out. If the turkey leg is too large for your Instant Pot, use a cleaver or heavy knife to break the end. (Note: It doesn't need to be fully severed—just have enough of a bend to fit comfortably into the pot.) Place the leg in the pot on top of the pork and shallot mixture, seal the lid, and press the poultry button.
After the cycle has completed, perform a manual release, carefully remove the lid. If you are happy with the quantity of drippings the turkey leg has released, remove it from the pot and set it aside. If not, reseal the pot for a second poultry cycle, release again, and remove the turkey leg. (Use the meat to season braised greens, beans, or soup.)
Using a measuring cup or glass, remove a small amount of drippings from the pot. Stir a heaping tablespoon of tapioca starch into the removed liquid to form a lump-free slurry, and stir that back into the Instant Pot. The liquid may retain enough heat, but if not, press the saute button and stir the mixture constantly over the heat to thicken it. Repeat the slurry process, stirring starch and additional stock into the drippings until it reaches your desired consistency. Gravy is achieved.