The recipe above uses pork stock to make a pork sauce. However, you can easily use whatever type of meat stock you like to create a sauce that pairs nicely with your protein. For example, the same approach outlined above works great if you use fortified chicken stock to make a honey Dijon chicken sauce to serve with chicken.
To make the pork stock I used for this sauce, I started with some storebought stock, and added carrots, celery, onion, bay leaves, pig ears, pig spine, and pig trotters. I then cooked this mixture down for ten hours. The final result was extremely collagen-heavy and incredibly flavorful.
If you are making your own stock, after it is strained, try pouring it carefully into ice cube trays and freezing them. You can then store the frozen stock cubes in a Ziplock bag in your freezer, using a cube or two whenever you need it.