Step 1 - Place the prietas in a pot so that they are firm between them and sauté with oil over low heat. Add carrot, onion, wine and beef broth, salt and pepper.
Step 2 - Cook the prietas in a covered pot over very low heat.
Step 3 - Cook for 10 minutes, add the chopped cilantro and cook for 10 more minutes.
Step 4 - Separately, in a frying pan lightly toast the flour and add water to form a thin sauce. Set aside.
Step 5 - Add a little of the cooking liquid to the roasted flour sauce to dilute it and then off the heat pour the sauce into the pot with cooked prietas, stirring to avoid lumps. Cook for 2 to 3 minutes.