The roast should be studded with the cloves at even intervals all over. Use of small paring knife to create small incisions in which the cloves can be inserted. Since the round is rather dry, it helps also to lard it with some fatty cured pork (see Notes).
In terra-cotta or enamel cast iron Dutch oven not too much bigger than the roast, brown the roast all over in the lard or olive oil. When the roast in nicely brown, add the onion, carrot, celery, garlic and parsley, and season everything generously with salt and pepper. Let these aromatics sauté until they are quite soft, turning the meat so that it absorbs their flavors. Then add a good splash of red wine and let it evaporate, again turning the meat so it absorbs the wine.
Add the tomato, enough to cover (or almost cover) the roast, along with a few more cloves if you like. Cover the pot and lower the heat so the liquid gently simmers. Let the roast braise until it is tender but not falling apart—this should take about 1-1/2 or 2 hours.
Taste and adjust for seasoning. Let the roast rest off heat for a few minutes, then slice as many portions as you think you'll need, arranging the slices on a serving platter, napping some of the sauce over them. Like any braised dish, garofolato can be made ahead and reheated when you're ready to eat.