for shanks, I'd braise them in the oven.
braising liquid is up to you but I'd start with some stock and finely chopped veggies/herbs.....some wine, etc.
Cook this until the veggies all but disintegrate......add more liquid as required.
Salt/pepper the shanks and sear quickly then add the braising liquid.
Into the oven at 350 for a couple hours (depends on how many, etc.
Cover or not dependent on the recduction of the liquid desired.
Don't overseason the stock......it will get salty as it reduces.