Preheat oven to 400 F. Place bones in a single layer on a sheet or roasting pan. Drizzle with olive oil to evenly coat.

Roast for 30 minutes, then, flip each bone over and roast for an additional 30 minutes.

Place chopped vegetables, roasted bones, bay leaf and cider vinegar and place in your slow cooker. Cover completely with water and set your slow cooker to low.

Simmer for 24 hours. Throughout simmering, add water as needed to keep all the ingredients submerged.

Once the broth has reached a dark rich brown color, turn off slow cooker.

Discard the bones, vegetables and bay leaf and strain through a cheesecloth. Cool the broth to room temperature.

Pour into jars and let cool in the refrigerator for at least 1 hour.

When you are ready to serve, skim the condensed fat off the top of the broth and heat to the desired temperature. Sip in a cup or add to your favorite recipe.