Pat the boneless short ribs dry with a paper towel and season each side generously with salt and pepper.
Drizzle the olive oil into a large pot and place over medium high heat.
Once heated, add the boneless short ribs and sear on each side until deeply golden.
Remove the short ribs to a plate and set aside.
Reduce heat to medium low and add the carrots, onion, and celery to the pot.
Cook, stirring occasionally, until softened.
Add the garlic and cook just until fragrant, 30 seconds to 1 minute.
Stir in the tomato paste until evenly coated and it starts to darken.
Slowly pour in the red wine and scrape the bottom of the pot with a wooden spoon to remove any browned bits. Simmer until the red wine reduces by half.
Pour in the beef stock, then the tomato passata. Season with the cocoa powder, thyme, oregano, Ancho chili, bay leaves, and additional salt (I usually add about a teaspoon), and pepper (about 1/4 teaspoon).
Bring the mixture to a simmer, then reduce heat to low and cover. Cook, stirring occasionally and skimming off any fat that rises to the top, for 3 hours, until the beef is tender and easily able to be shredded with a fork.
Uncover the pot and carefully use two forks to shred the beef into smaller, bite size pieces. If your pot is ceramic or susceptible to scratching, remove the beef to a rimmed plate or pan, shred, then place back in the pot.
Increase heat to medium low and simmer for another 30 minutes to thicken, stirring occasionally. Adjust seasonings to taste, adding more salt and pepper if needed.
Serve warm with desired base such as pasta or polenta and with a fresh grating of Parmesan and chocolate over the top.