To begin, combine the minced garlic, chopped onion, cumin, black pepper, salt, Worcestershire sauce, and beer in a large bowl. Place the beef in the mixture, ensuring it is fully coated. Cover and marinate in the refrigerator for at least 6 hours, preferably overnight, for deeper flavour infusion.

Remove the beef from the marinade, pat it dry with paper towels, and set the marinade aside for later use. Allow the beef to come to room temperature for 30 minutes before cooking. This step ensures even cooking throughout the roast.

Heat the vegetable oil in a large, heavy bottomed pot over medium high heat. Sear the beef on all sides until a deep golden brown crust forms, about 2-3 minutes per side. This caramelization enhances the depth of flavour in the final dish.

Sprinkle the brown sugar evenly over the beef and let it melt slightly, creating a glaze. Flip the beef gently to coat it evenly with the caramelized sugar. Be careful not to let the sugar burn; adjust the heat if necessary.

Add the reserved marinade, cola, beef stock, tomato paste, raisins, and bay leaf to the pot. Stir to combine and bring the mixture to a simmer. The cola's sweetness balances the savoury flavours, creating the dish's signature sauce.

Reduce the heat to low, cover the pot, and let the beef cook gently for 2 to 2.5 hours, turning it occasionally. If the sauce thickens too much, add small amounts of water or stock to maintain a rich, pourable consistency.

Once the beef is tender and can be easily pierced with a fork, remove it from the pot and set it aside to rest for 10 minutes. Strain the sauce if desired, then return it to the pot to thicken slightly over medium heat.

Slice the beef thinly against the grain and serve it with the rich, dark sauce drizzled generously over the top. Pair with white rice or coconut rice and garnish with fried plantains, or avocado for an authentic Colombian touch. For added presentation, sprinkle finely chopped parsley or cilantro on top.