Pork is a base ingredient and you cannot make it. You can get Pork from killing Wild Boars, and using a Butcher Knife to harvest the Pork from the body. You can also use alternate meat like Wolf Meat, Lamb Meat and Beef. Press F2 and click the Crafting Notes on the lower right corner of the pop-up window, type Pork to see all the food you can cook with it.