In a large Dutch oven heat 1 tbls. of the oil over medium heat. Add the onion and garlic; sauté until soft, about 10 minutes. Remove the onions from the pan and heat the remaining oil. Brown the beef in 2 batches; remove from pan.
Put the onions back into pan and add tomatoes, sherry, plum and hoisin sauces, the salt, pepper, and hot pepper flakes. Simmer the sauce for 10 minutes. Add the beef, cover and simmer 1 hour, stirring occasionally. Uncover and continue cooking 30 minutes.
While short ribs are cooking, prepare the carrots. Bring a pan of water to boil, add the carrots and cook 5 minutes. Drain and rinse with cold water to stop the cooking.
Add the carrots to the meat and continue to cook 15 minutes. Sprinkle with sesame seeds and serve meat and sauce over the hot rice.