In a large pot, combine 4 liters of water, kosher salt (60 g) and brown sugar (30 g). Warm gently over medium heat, stirring until salt and sugar dissolve. Remove from heat and let cool to room temperature. Add bay leaves, black peppercorns, allspice, smashed garlic, halved onion, chopped carrot and celery to the cooled brine.

Brine the tongue (optional but recommended)

Place the beef tongue in a non-reactive container or a large zip-top bag. Pour the cooled brine over the tongue, ensuring it is fully submerged. Refrigerate for 8–12 hours (overnight) to season and tenderize. If short on time, proceed without brining but increase cooking time by ~15–30 minutes.

Rinse and start cooking

After brining, remove the tongue and rinse under cold water. Put the tongue into a clean large pot and cover with fresh cold water (about 3–4 cups more than needed to fully submerge). Add 1 halved onion, the reserved carrot and celery if desired, and one additional bay leaf. Bring to a simmer over medium heat; do not boil hard — maintain a gentle simmer to keep the meat tender.

Simmer until tender

Cover partially and simmer gently for 2 to 3 hours for a 1 kg tongue, until a knife or skewer slides in easily and the outer skin begins to loosen. Skim any foam occasionally. If you did not brine, expect closer to 3 hours; if larger than 1 kg, increase time accordingly.

Rest and peel

Remove the tongue from the cooking liquid and let it rest until warm but manageable (15–20 minutes). Using a sharp knife, cut away the thick outer skin from the base toward the tip — it should come off in sheets. Trim off excess fat and the root end if present.

Finishing & Serving

Slice and season

Slice the peeled tongue across the grain into 1/4-inch (6 mm) slices for sandwiches or thinner for tacos. Arrange on a platter, drizzle with 2 tablespoons apple cider vinegar or lemon juice, sprinkle with chopped parsley, coarse salt and freshly ground black pepper to taste.

Optional pan-fry (crisp edges)

For a browned finish, heat 1 tablespoon neutral oil in a heavy skillet over medium-high heat. Sear slices 1–2 minutes per side until golden and slightly crisp at the edges. This enhances flavor and texture for tacos or sandwiches.

Serve

Serve warm on toasted bread or tortillas with mustard, chimichurri or your preferred condiment. Refrigerate leftover tongue in an airtight container for up to 4 days; slices may be reheated gently in a skillet or broth.