Heat oil in a large Dutch oven over medium-high heat. Sprinkle brisket with salt and pepper. Add brisket to pan; cook 5 minutes, turning to brown on all sides. Remove from pan. Add onion to pan; sauté 8 minutes or until browned. Return beef to pan. Add Madeira, broth, garlic, and bay leaf to pan; bring to a simmer. Cover and bake at 350° for 1 1/2 hours.
Add squash, potato, and apricots to pan. Cover and bake an additional 1 hour or until vegetables are tender. Remove bay leaf from pan; discard. Remove brisket from pan; cut diagonally across the grain into thin slices. Sprinkle with parsley. Serve with vegetables and cooking liquid.