Prepare the Corned Beef: Use a sharp knife to trim excess fat from the corned beef. Pat dry with paper towels.

Brown the Beef: Heat oil in a Dutch oven over medium-high heat. Add corned beef and sear for 1–2 minutes per side until lightly browned.

Add Aromatics: Place onion, cloves, garlic, thyme, bay leaves, and peppercorns into the pot. Cover the beef with water.

Simmer Until Tender: Bring water to a boil, then reduce to low. Simmer gently for 3–4 hours until the meat is fork-tender. Alternatively, cover the pot and place in a 300°F oven for 4–5 hours. Add carrots during the last hour if desired.

Prepare the Glaze: While the beef cooks, whisk together blackberry preserves, Dijon mustard, brown sugar, soy sauce, and black pepper in a saucepan. Bring to a boil, then simmer 7–10 minutes until thickened.

Glaze and Broil: Transfer cooked corned beef to a foil-lined baking sheet. Brush generously with the glaze. Broil for 5–7 minutes until the glaze caramelizes.

Rest and Slice: Remove beef from the oven. Let it rest for 10–15 minutes before slicing. Brush with more glaze if desired.

Serve: Plate the corned beef with carrots, roasted potatoes, or cabbage. Garnish with fresh herbs for extra color.