Season the oxtail with salt and pepper.
In a large heavy pan or cast iron heat a splash of olive oil on medium high heat
Lightly dust the oxtails with flour (shake away excess) and sear each piece in the hot oil until nicely browned, about 30 seconds per side.
Remove the oxtails and let the pieces rest.
In the same oil and pan, saute the leek, onion, garlic, red pepper, and tomato for about 10 minutes.
Add the carrots, bay leafs, ginger, and cloves and saute 1 minute.
Add the oxtails back to the pan and cover with the wine and stock.
Bring to a boil, then cover and reduce to a slow simmer.
Cook the rabo de toro for 3 hours and then check to see if it is falling away from thebone. It may need another hour or so if the meat is very tough.