Brown the ribs in the olive oil in a stock pot on all sides. Remove to a paper towel lined plate. Remove the pan from the heat and carefully add the sherry and sherry vinegar. Return to the heat and cook, scraping up any browned bits from the bottom of the pan, for about 5 minutes. Be careful as the alcohol may ignite when returned to heat. If it ignites, wait to stir until the flames die out.
Add the rest of the ingredients, except for the butter, including the browned ribs, to the pot. Bring the liquid to a simmer, cover, and cook for about 3 hours, or until the ribs are very tender.
Season with salt and pepper. Remove the ribs from the pot and set aside on a plate. Strain the liquid and return to the pot. Add the butter and stir until the butter is incorporated. Add the ribs back to the pot and coat well with the sauce. Serve.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Jason Rogers of Olives, Aspen, Colorado