Preheat the oven to 350 degrees.
Grease a 9- by 13-inch baking pan with the butter. Combine the beef, pork, onions, bell peppers, garlic, eggs, cream, bread crumbs, parsley, Essence, salt, and pepper and gently but thoroughly mix ingredients together. Shape the mixture into a loaf and place in the prepared pan. Pour the stock over the top and bake for 1 to 1 1/2 hours, basting occasionally with the pan juices. Remove from the oven. Carefully transfer the meatloaf to a platter. Strain the cooking juices remaining in the baking pan through a fine sieve and transfer to a small saucepan. Transfer to the stovetop over high heat. In a small bowl, whisk together the flour and the water. Add to the pan and whisk to blend. Cook, stirring constantly, until the mixture thickens.
Season the gravy with salt and pepper to taste. Pour over the meatloaf and serve.
The meatloaf will keep, refrigerated, for three to four days.
Make 6 servings