Preheat the oven to 350 degrees F. Grease a roasting pan with the butter. In a mixing bowl, add beef, pork, onions, peppers, garlic, eggs, cream, and bread crumbs. Blend thoroughly. Season the mixture with salt and pepper. Shape the mixture into a loaf and place on the prepared pan. Pour the stock over the top and place in the oven. Place in the oven and bake for about 1 to 1 1/2 hours, basting occasionally. Remove the pan from the oven. Using a long spatula, remove the meat loaf from the pan. Place the roasting pan on the stove, over high heat. In a small bowl, whisk the flour with 2 tablespoons water. Whisk the slurry into the gravy. Bring the liquid to a boil and cook for few minutes, stirring constantly. Season the gravy with salt and pepper. Slice the meatloaf in to 8 pieces. Serve two slices of meat loaf per person with a spoonful of gravy.