Ingredients

• 1/4 cup chopped onion
• 2 tablespoons liquid smoke flavoring
• 2 tablespoons Worcestershire sauce
• 2 cloves garlic, minced
• 1 tablespoon chili powder
• 1 tablespoon celery seed
• 1 tablespoon ground chipotle pepper
• 1 teaspoon salt
• 2 pounds beef brisket, or more to taste
• 2 tablespoons vegetable oil
• 1/4 cup apple cider vinegar
• 1 (14.5 ounce) can canned diced tomatoes
• 1 1/2 cups water
• 2 bay leaves
• 1 tablespoon all-purpose flour, or as needed

Instructions

1. Combine onion, liquid smoke flavoring, Worcestershire sauce, garlic, chili powder, celery seed, chipotle pepper, and salt in a bowl until marinade is smooth. Place brisket in a shallow glass dish and pour marinade over brisket. Cover dish with plastic wrap and refrigerate, 8 hours to overnight.
2. Heat oil in a large skillet over medium-high heat. Scrape onion from the brisket, reserving onion and marinade. Cook brisket in the hot oil until browned on all sides, about 10 minutes. Transfer brisket to a slow cooker on Low.
3. Pour marinade with onion and vinegar into the skillet and bring to a boil while scraping the browned bits of food off of the bottom of the pan with a wooden spoon. Cook mixture until onion is tender and liquid is reduced by 3/4, 5 to 10 minutes.
4. Mix vinegar-onion mixture, tomatoes, water, and bay leaves into slow cooker.
5. Cook on Low until brisket is very tender, at least 6 hours.
6. Strain liquids from slow cooker into a saucepan; bring to a boil. Whisk enough flour into liquid until desired gravy consistency is reached, about 5 minutes.
7. Shred brisket with a fork and serve with gravy and tomato-onion mixture.