Preheat oven to 375 degrees.

In a dutch oven or other heavy baking pan large enough to hold brisket, heat 1 tablespoon oil in oven 10 minutes. Pat brisket dry and season well with salt (I used about 4 teaspoons) and pepper on the top and bottom. Roast brisket in pan, uncovered, 30 minutes.

While brisket is roasting, in a large heavy skillet cook onions in remaining 2 tablespoons oil over moderately high heat, stirring, until softened and beginning to turn golden. Reduce heat to moderate and cook onions, stirring occasionally and reducing heat if necessary, until deep golden, about 20 minutes more. Stir in garlic, paprika, salt, and pepper and cook 1 minute. Stir in water and wine and bring to a boil. Spoon onion mixture and chopped tomatoes over brisket and bake, tightly covered, 3 ½ hours, or until brisket is tender. (Check pan every hour and if necessary, add more water.) Remove brisket from oven and let cool in onion mixture 1 hour.

Remove brisket from pan, scraping onion mixture back into pan, and chill, wrapped in foil, overnight. Spoon onion mixture into a 1-quart measure and chill, covered, overnight.

Preheat oven to 350 degrees. Discard fat from onion mixture and transfer to a blender. Add enough water to the blender to measure 3 cups total. Blend until smooth.

Slice the brisket against the grain as thick or thin as you prefer. In a large ovenproof skillet heat gravy until hot, add brisket and heat in oven 30 minutes. Or you can continue to heat on the stove, covered until heated through.