procedure

In a small bowl, mix together salt, pepper, paprika and cayenne. Season brisket generously on all sides with salt mixture. (Use about 2 tablespoons and reserve remaining mixture.) If possible, wrap and refrigerate several hours or overnight, then bring to room temperature.
Heat oven to 300 degrees. Place brisket in a shallow roasting pan or earthenware baking dish. Pour wine and 2 cups water over the brisket, then add cloves, garlic, bay leaves and allspice berries.
Scatter about 1/3 of the sliced onions over brisket. Cover with foil or a tight-fitting lid. Place in oven and bake for about 3 hours or until meat is quite tender when probed with a fork. (Be careful not to overcook; you want slices, not shreds.)

Meanwhile, place a large skillet over high heat and add olive oil. Add remaining onions and season with remaining salt mixture. As onions begin to brown, reduce heat to medium. Cook, uncovered, turning onion slices with a spatula every few minutes until caramelized and fork-tender, about 15 to 20 minutes. Add 1/2 cup water to onions and simmer a few minutes more. (For more flavor, use broth from the brisket pan instead.) Onions may be prepared in advance and reheated.
To serve, transfer brisket to a cutting board. Trim extraneous fat from meat. With a large knife, cut meat across the grain into 1/4-inch slices. Strain braising liquid into a saucepan (discard solids left in strainer) and skim any rising fat from surface.
Arrange sliced meat on a platter. Cover with caramelized onions and ladle some hot braising liquid over. Garnish with parsley sprigs and sprinkle with scallions, if using. Serve remaining juices separately.