Scatter half the onion rings over the bottom of the pan. Place the brisket over the onions; sprinkle with pepper. Spread the remaining onions over the brisket. Stir the chili sauce and beer together and pour over the meat.
Cover and roast until the veal is fork tender, about 2-1/2 to 3 hours, basting with the pan juices several times.
Remove the brisket to a carving board. Skim the fat from the surface of the pan juices with a spoon. Transfer the defatted juices and onions to a saucepan and cook over high heat until slightly thickened and reduced to 2-1/2 cups.
Thinly slice brisket across the grain; pour 1/4 cup of onion gravy over each serving.