1. Preheat oven to 325 degrees F. Line a cookie sheet with foil and set aside.
2. In a large skillet over medium-high heat, warm olive oil. Add brisket, fat side down, to skillet. Cook until nicely browned (about 3 to 4 minutes). Using tongs, turn brisket and cook on opposite side until browned.
3. Place brisket in a 9 x 13 inch baking pan, fat side down. In a medium mixing bowl, combine garlic, celery salt, mustard, paprika, brown sugar, tomato paste, thyme, marjoram, oregano, wine, 1/4 teaspoon black pepper, and carrots. Mix well and pour mixture over brisket. Cover baking pan with a sheet of foil and place pan in oven.
4. After 1 1/2 hours, carefully remove foil. Using tongs, turn brisket. Re-cover and continue cooking.
5. Prepare the caramelized onions. In a large mixing bowl, combine onions, oil, vinegar, sugar, salt, and remaining pepper. Toss well to coat onions.
6. Put onions onto cookie sheet and place in oven on lower rack, beneath brisket. Stir onions after 30 minutes of cooking - they will start to wilt and turn golden.
7. After an additional 45 minutes, stir onions again. Take brisket out of oven. Using tongs, transfer brisket to a platter. Brisket should have cooked for a total of 2 hours, 45 minutes. Cover brisket with foil and let it rest for 15 minutes. Onions should remain in oven; cook for an additional 15 minutes, then check to see if they are tender.
8. To separate fat from cooking juices, pour brisket juices into a freezer-safe container and mix with ice water. Place juices in freezer. Let sit undisturbed for at least 15 minutes. Alternatively, pour juices into a gravy separator to strain out fat.
9. Slice brisket against the grain into 1/4-inch-thick slices. Return slices to baking pan.
10. Use a shallow spoon to skim and discard any fat that has risen to the surface of the cooking juices container. Slowly pour cooking juices over brisket slices. Stir onions and spoon them over sauced brisket.
11. Return baking pan to oven and roast brisket, uncovered, an additional 25 to 30 minutes, until everything is heated through.
12. To serve, lift slices with a spatula and then spoon additional sauce around brisket. Serve this saucy brisket over egg noodles for a real treat.
Source: Hannaford fresh Magazine, March - April 2007