Preheat the oven to 300?F.
With a small, sharp knife, make 1 1/2-inch-deep slits around the outside of the roasts. Insert the cloves of garlic into the slits. Rub the roasts with the salt and black pepper on all sides.
Heat a large Dutch oven or other heavy, wide pot over high heat. Add 2 tablespoons oil and heat. Add the roasts and sear on all sides, about 4 minutes per side. Remove the roasts from the pan and sprinkle with Essence on all sides. Reduce the heat to medium-high. Add the remaining 2 tablespoons oil and the flour and cook, stirring constantly, until chocolate brown in color, about 5 minutes. Add the onions, celery, and carrots and cook until the vegetables begin to soften, about 5 minutes. Add the beef broth, tomato paste, and bay leaves and stir to blend. Return the roasts to the pan and top with the potatoes.
Cover and bake for 3 to 4 hours, depending on how tender you prefer your meat. Remove the pot from the oven and remove the meat and potatoes; set aside. Place the pot on the stove over medium-high heat and cook until the gravy is reduced slightly and begins to thicken, about 10 minutes. Remove the bay leaves. Puree the gravy with an immersion blender or in batches in a bar blender. Slice the meat and cut the potatoes into bite-size pieces; return to the pot with the gravy. Serve warm.
Makes about 10 servings