Special equipment: wood pilon, for mashing plantains.
Heat vegetable oil until hot, and then fry the plantains for 10 to 15 minutes. Transfer to a pilon with the beef broth and garlic oil and mash together until combined. Mix in some chicharrones, if using. Mold the plantain mixture into an 8-ounce bowl, then plate the mofongo.
Cook the skirt steak on a flat skillet over high heat on one side. Sprinkle the top with salt, flip the steak and drizzle the top with garlic oil. Cook until desired doneness, then flip once more, spread with garlic oil and season with salt. Cut into pieces and drizzle with Creole sauce. Place into the plated mofongo and serve with avocado.