Step 1: Prepare the Beef

Trim the Beef: Begin by trimming any excess fat from the chuck roast. Removing the fat prevents the sauce from becoming greasy while ensuring the beef absorbs more of the flavorful braising liquid.
Season Generously: Liberally season both sides of the roast with salt and pepper. This initial seasoning is crucial for infusing the beef with flavor as it cooks.

Step 2: Sear the Roast

Heat the Oil: Warm 2 tablespoons of olive oil in a large skillet or Dutch oven over medium-high heat. The oil should shimmer when ready.
Sear the Beef: Place the seasoned roast in the hot skillet. Sear for 3-4 minutes on each side until a golden crust forms. This step locks in the juices and enhances the beef’s flavor.
Transfer the Roast: Carefully remove the seared beef and place it in your slow cooker or roasting pan, ready for braising.

Step 3: Sauté the Aromatics

Cook the Onions: In the same skillet, add the sliced onions and sauté for 5-7 minutes over medium heat. Stir occasionally to ensure even caramelization.
Add Garlic and Carrots: Toss in the minced garlic and carrot chunks, stirring for another 2-3 minutes until fragrant. This step builds the aromatic base of the sauce.
Deglaze the Pan: Pour in the balsamic vinegar. Use a wooden spoon to scrape up any browned bits from the skillet’s bottom—these bits are packed with flavor and will enhance the sauce.

Step 4: Combine the Ingredients

Assemble in the Pot: Pour the sautéed onion mixture over the beef in the slow cooker or roasting pan. Add the fresh cranberries, rosemary, thyme, bay leaves, and optional red pepper flakes.
Mix the Sauce: In a small bowl, whisk together the beef stock, brown sugar, and Dijon mustard. Pour this mixture evenly over the beef and vegetables, ensuring everything is well-coated.

Step 5: Slow Cook the Roast

Cover and Cook:

• Slow Cooker: Cook on low for 6-8 hours or on high for 3-4 hours.
• Oven: Cover the roasting pan tightly with aluminum foil and bake at 325°F (165°C) for 3-4 hours.
  Check for Tenderness: The roast is ready when it can be easily shredded with a fork.

Step 6: Finish the Sauce

Remove the Beef: Carefully lift the roast out of the pot and transfer it to a platter. Tent with foil to keep warm.
Thicken the Sauce: Skim any excess fat from the surface of the sauce. For a thicker consistency, transfer the sauce to a saucepan and simmer over medium heat for 5-10 minutes. Adjust the seasoning with salt and pepper as needed.

Step 7: Serve and Garnish

Slice or Shred: Slice the roast into thick portions or shred it into chunks, depending on your preference.
Plate the Dish: Serve the beef with a generous ladle of sauce and vegetables. Garnish with fresh parsley and additional cranberries for a festive touch.