Step 1In a large bowl, toss the oxtail with 2 tablespoons olive oil, one-fourth cup red wine and 1 tablespoon salt and 1 teaspoon pepper, or to taste. Let stand for 30 minutes.
Step 2Heat a roasting pan on the stove over medium-high. Add 2 tablespoons olive oil. Carefully add the oxtail to the pan (it should start sizzling and may spit hot oil). Sear on all sides until brown and caramelized, about 10 minutes. Remove the oxtail from the pan.
Step 3Add the onion, carrot and celery root and cook until soft and lightly caramelized, eight to 10 minutes. Add the garlic and cook until aromatic, 2 to 3 minutes more, making sure the bottom of the pot is not burning. Meanwhile, heat the oven to 325 degrees.
Step 4Add the bay leaf and thyme sprigs to the pot, deglaze the pan with the rest of the red wine and cook it down to a glaze, about 5 to 7 minutes. Return the oxtail to the pot, and add the chicken stock to cover. Bring to a simmer and place a cover or foil over the pan.
Step 5Place the roasting pan in the oven and braise 3 to 4 hours, until the meat is nearly falling off the bone. Remove the pan and skim the fat off the top with a ladle. Remove the meat from the liquid to a bowl, and allow it to cool slightly. Strain the liquid out of the pan into a medium saucepan over low heat.
Step 6Pick only the good meat off of the ox bones, removing the fat and sinew. Add good meat to the liquid.
Step 7Mash all the vegetables that were braised with the meat with your hands and add them back to the liquid as well. Season this mixture to taste with salt and pepper, and cook over low heat until the contents have a ragu-like consistency. Set aside for assembly, or keep refrigerated until ready to use.
Step 1In a medium saute pan, slowly reduce the Port at a slow simmer with the brown sugar and black peppercorn until it reduces to about one-half cup and has a syrupy consistency, about 15 minutes. Strain and set aside.
Step 1In a bowl, toss the parsley leaves and sliced shallots with the olive oil, lemon juice and salt and pepper to taste. Set aside.
Step 2Lightly toast the sliced baguette. Drizzle the slices lightly with olive oil. Top each slice with about 1 1/2 tablespoons braised oxtail, making sure the liquid gets into the bread. Add 2 heaping teaspoons parsley-shallot salad on top of the oxtail mixture. Drizzle each slice with about one-half teaspoon Port reduction and serve.