Preheat oven to 325 degrees F.

Season both sides of the oxtails, liberally with 2 teaspoons salt and 2 teaspoons black pepper. Set a large heavy duty dutch oven over medium high heat, with 2 tablespoons olive oil. Once hot, sear the oxtails in batches, until both sides are browned and crispy. You're not looking to cook them all the way through, just give them a nice brown color. I'd say about 2 minutes per side. Transfer to a plate or platter and continue browning the rest.

Add the remaining 2 tablespoons olive oil to the pot, and throw in the pancetta, onions, carrots and diced celery. Cook, stirring often, util the veggies start to brown and begin to soften just slightly. Stir in the tomato paste and cook for a minute longer. Deglaze the pot with the red wine, scraping the bottom with a wooden spoon to pick up all of those bits and pieces. Simmer until the wine has reduced and evaporated by half, about 5 minutes. Add marjoram, cloves, cinnamon and remaining salt and pepper. Stir until well combined, and add the tomatoes, breaking the whole tomatoes as best you can with your hands. You can also break them up with the wooden spoon.

Return the oxtails to the sauce, tucking them into the sauce, making sure they're all in an even layer. Bring the liquid to a boil, cover the pot, and place it in the oven. Braise for 1 1/2 hours, turning the oxtails every now and then.

Uncover the oxtails, scatter the top with the remaining celery and cover and return to the oven until the meat is tender and falling off the bone, about 30 to 60 minutes longer.

Remove from the oven, and let rest for about 10 to 15 minutes to cool down a bit. Give it a taste and sprinkle with salt and pepper as needed. Serve with crusty bread on the side for dipping. Enjoy!