Preheat oven to 375 F. Roast bones on a sheet pan for 30-45 minutes until the meat is thoroughly cooked and the fat is partially caramelized—this will add rich and deep flavor to the broth.
In a large stock pot add bones, vegetables, vinegar, and spices. Use a wooden spoon and some water to scrape all the residual bits of meat and fat stuck to the pan and add it to the pot as well. (This is what is known as a fond. It is full of flavor and should not be wasted.) Fill pot with cold water till it covers everything. Simmer on low heat for 8-24 hours.
When the broth is ready, strain everything through a colander and dispose of solid ingredients. (If using oxtails, you can fish those out and snack on the meat. The shiitakes are also a nice snack for the cook!) Strain the liquid once more through a fine strainer or cheesecloth to remove any last solid pieces.
Let the liquid settle in a pot or container. You will see the fat and broth separate. You scan skim the fat away with a ladle or let the whole thing cool in the fridge and cut it away with a knife in one solid block. Save the fat, otherwise known as tallow, and use it for cooking! It is full of flavor and great for roasted potatoes and sauteed veggies.
Your beef broth is now ready for soup or gravy. If using for soup, make sure to taste the broth and add any salt as needed.
TO MAKE GRAVY:
Heat broth in a pot to a light boil. Add a splash of red wine, salt, and pepper to taste.
Whisk in *roux, cornstarch, or arrowroot powder until you reach your desired consistency.
Roux is equal parts butter and flour that has been light cooked in a pan to activate the gluten. For an average gravy consistency, start with 2 tablespoons of roux for one cup of broth.
Optional; add a handful of thinly sliced crimini or white button mushrooms, letting them cook in the broth or sauté beforehand in garlic butter.
Femur bones, rib bones, ox tails, and even beef scraps and trimmings are all acceptable for this recipe. Traditional French mirepoix is a mixture of onion, celery, and carrot. The classic ratio is 2 parts onion, 1 parts celery, 1 part carrot. For deeper flavor, you can lightly char the side of the onion quarters before it goes in the pot. Do this in a dry, cast iron pan on high heat. Starting with cold water and using low heat is import for a slow release of flavor. This will result in a rich broth. Do not let it boil, but instead create enough heat to allow for small champagne bubbles to form.