2 T. vegetable oil
1 5-6 lb first-cut or flat-cut brisket, cut into 3 pieces
kosher salt and ground pepper, to taste
4 cloves garlic, smashed and peeled
12-oz bottle stout beer
4 stalks celery, cut into large pieces
2/3 C. packed dark brown sugar
1/2 C. tomato paste
1/2 C. red wine vinegar
1/3 C. dijon mustard
1/3 C. soy sauce
2 bay leaves
1 t. paprika
1. Heat the vegetable oil in a large skillet over med-high heat. Season the brisket with salt and pepper, then brown on all sides, about 10 minutes, adding garlic in the last 2 minutes. Transfer the meat and garlic to a 5-6 qt. slow cooker. Pour the beer into the skillet and simmer 30 seconds, scraping up the browned bits from the pan; add the beer mixture to the slow cooker.
2. Nestle the celery around the meat and add the brown sugar, tomato past, vinegar, mustard, soy sauce, bay leaves and paprika. Stir, then cover and cook on low 8 hours or on high 6 hours. Transfer the meat to a cutting board and let rest 10 minutes, then thinly slice.