Ingredients

• 6 garlic cloves
• 2 tablespoons brown sugar
• 2 tablespoons Dijon mustard
• 2 tablespoons olive oil
• 1 tablespoon freshly ground black pepper
• 1 tablespoon ground cumin
• 1 tablespoon paprika
• 1 teaspoon cayenne pepper
• 1/4 cup kosher salt, plus more
• 1 8–10-lb. untrimmed flat-cut brisket
• 2 onions, thinly sliced
• 1 12 ounce can lager

Instructions

1. Finely chop garlic in a food processor. Add brown sugar, mustard, oil, black pepper, cumin, paprika, cayenne, and 1/4 cup salt and process until smooth. Rub all over brisket, working into crevices. Wrap in plastic; chill 1–2 days. Let meat sit out until room temperature, about 1 hour.
2. Preheat oven to 325°. Scatter onions in a large roasting pan and set brisket, fat side up, on top. Add beer; cover with foil. Braise until meat is very tender, 5–6 hours. Remove from oven; heat broiler. Broil brisket, uncovered, until top is browned and crisp, 5–10 minutes.
3. Let brisket cool slightly. Remove from pan and shred or slice. Remove onions with a slotted spoon; mix into brisket. Taste and moisten with some cooking liquid and season with salt, if needed.
4. Do ahead: Brisket can be braised 1 day ahead. Let cool; cover and chill. Reheat, covered, at 325° for 1 1/2 hours.