Start preparing your Spanish stew by generously seasoning the ribs with salt and pepper.
Dust the ribs with some flour, making sure that all sides are coated.
Heat the olive oil on a medium to a large pan over medium-high heat.
Once the oil is ready, add the ribs carefully and brown them on all sides.
Remove the ribs from the pan and set them aside.
Using the same pan and oil, add the garlic and onion.
Cook until the onions turn soft, then add the celery and carrots.
Cook for about 3 minutes, then add the: chopped tomatoes, tomato paste, thyme, bay leaf, peppercorns, chili flakes, cloves, salt, and pepper.
Cook for about 5 minutes, mixing frequently.
Add the browned ribs back into the pan and pour the red wine and sherry directly into it.
Mix and let the wine and sherry reduce --- the sauce would turn noticeably thicker at this point.
Pour the stock, then mix to combine.
Cover the pan with a lid, then bring to a boil.
Adjust the heat and let your Spanish stew simmer for about 2 hours or until the beef becomes tender.
On the last 45 minutes of cooking, add the potatoes, taste, and adjust the seasoning.
Place the lid back and continue simmering.
Transfer your Spanish beef stew into serving plates and enjoy!