In a large heavy frying pan, heat oil over medium high heat. When the oil is hot, brown the beef on all sides. If the brisket is too large, cut it in half first and brown in two stages. Place the meat in a large casserole dish with a lid.
Add onions to the drippings in the frying pan. Saute over medium heat until the onions are beginning to brown. Stir in garlic and cook for 2 to 3 more minutes. Pour over the brisket in the casserole dish.
Sprinkle soup mix over the browned onions and meat. Arrange the apricots on top of the soup mix. Pour enough water AROUND outside of meat, not on top, to cover the sides of brisket. Cover with lid.
Bake at 160 C / Gas 2 1/2 for 1 hour. Check liquid; if dish is starting to look dry, add a bit more water around meat. Cover and cook 1 more hour. Remove lid and stir apricots into gravy. Leave uncovered and cook for 1 more hour. Stir gravy again and add more water if the gravy is too thick. Meat should be very tender; if necessary, bake for an additional 30 minutes. Cut across grain to serve.