In a large bowl, combine the boneless top sirloin roast with the crushed beef bouillon cube, browning sauce, salt, black pepper, minced garlic, chopped onion, fresh thyme, scotch bonnet pepper, and allspice berries. Massage the seasoning into the meat and cover it with cling film. Allow the roast to marinate for at least two hours or ideally overnight in the refrigerator for enhanced flavor.

Heat a heavy pot over medium-high heat and add vegetable oil. Once the oil shimmers, carefully place the marinated roast into the pot, searing it on all sides for about 5-7 minutes until it’s beautifully browned and caramelized.

In the same pot, reduce the heat to medium and add the chopped carrots, celery, remaining onion, and minced garlic. Sauté for 5-6 minutes until the vegetables begin to soften and the onions become translucent.

Pour in beef broth, using a wooden spoon to scrape up any browned bits stuck to the bottom of the pot. Return the seared roast to the pot and bring to a gentle simmer.

Cover the pot with a tight-fitting lid, reduce the heat to low, and let the roast slow cook for 2.5 to 3 hours. Check the liquid levels halfway through.

When the beef is nearly tender, gently add the skin-on baby potatoes to the pot. Cover again and let them cook alongside the roast for another 30-40 minutes until fork-tender.

Once the pot roast is fork-tender, allow it to rest for 10-15 minutes before slicing it into thick pieces. Serve hot with your favorite sides.