Preheat oven to 325°. Season beef on both sides with 1 teaspoon each salt and cracked pepper. Heat oil in a 4- to 5-quart Dutch oven. Brown meat well on both sides, cutting in half to fit if necessary. Remove from heat; turn meat fat side up. Sprinkle with sage and spread with mustard. Add onion, carrots, celery and garlic to pot.Advertisement
In a medium bowl, whisk together ale, the water and tomato paste. Pour mixture over meat. Bring to boiling over high heat. Cover and transfer to oven. Bake for 3 1/2 to 4 hours or until fork tender.
Transfer meat to a cutting board to cool slightly. Meanwhile, prepare sauce by pureeing cooking liquid and vegetables in the Dutch oven with an immersion blender (or cool 15 minutes and transfer to a blender). Season to taste. TO SERVE IMMEDIATELY: Thinly slice meat across grain. Arrange on a platter and top with some sauce. Top with Celery-Horseradish Garnish if desired. Pass remaining sauce. TO SERVE SOON: Thinly slice meat across grain. Arrange in a casserole dish or on an oven-safe platter. Top with some sauce and cover with foil. Keep warm in a 275° to 325° oven for up to 1 hour. Top with Celery-Horseradish Garnish if desired. Pass extra sauce, rewarmed if necessary. TO SERVE LATER: Wrap cooled meat and transfer sauce to a covered bowl. Chill up to 2 days. To reheat, slice beef across grain; arrange in a casserole dish. Top with sauce (remove congealed fat first) and cover with foil. Warm in a 325° oven for 1 hour or until heated through. If you like, transfer beef to a platter and sauce to a pitcher. Top with Celery-Horseradish Garnish, if desired.
In a small bowl, combine 3/4 cup chopped celery leaves, 1/3 cup chopped fresh parsley, 1 tablespoon prepared horseradish and 1/2 teaspoon kosher salt.