Generously season both sides of the meat with the Essence, salt, and pepper. Lay steaks out on a clean surface with the grain running horizontally toward you in order to slice the cooked Matambre across the grain for more tender meat. Scatter 1 tablespoon of the garlic over both steaks and cover with spinach leaves, leaving a 1/2-inch margin. Top each steak with the carrots and eggs, and sprinkle with cayenne pepper. Carefully roll the meat over the filling in a tight, jelly-roll style and secure closed with kitchen string.
In a heavy Dutch oven or casserole, cook the bacon until the fat is rendered and brown, about 4 minutes. Remove the bacon and drain on paper towels.
Add the rolled steaks to the hot bacon fat and cook until browned on all sides, about 3 minutes. Remove the steaks and set aside.
Add the onions to the fat in the pan and cook, stirring, for 3 minutes. Add the remaining 2 tablespoons of garlic, the bay leaves and thyme, and cook, stirring, for 1 minute. Deglaze the pan with the red wine, scraping the bottom and sides to loosen the browned particles. Add the stock and bring to a boil.
Add the steaks to the pan and reduce to a simmer. Cover and slowly simmer until the meat is fork-tender, about 1 1/2 hours, turning meat once halfway through. Transfer the steaks to a cutting board and let rest for 10 minutes before removing the kitchen strings and carving.
Return the baking dish to the heat and bring to a boil. Cook until reduced and thickened, 5 to 10 minutes. Remove the reduced sauce from the heat, add the reserved bacon, and adjust the seasonings, to taste.
To serve, arrange the carved meat on 4 or 6 large plates. Spoon a little of the thickened sauce over the meat and top with the onions. Garnish with the chopped parsley and serve with the Salsa Criolla and Grilled Eggplant on the side.
Yield: 4 to 6 servings