Kidneys clean of skins and fat, cut to length and washed. Pour with water and a little vinegar, boiled for a few minutes, and again washed. Dried and cut into pieces. Put them in the pressure cooker in which pre-heated the oil, sprinkle with salt and pepper and sauté until graying. Add diced onions, carrots and celery. Stews while the dish remains of fat. Add tomato paste and flour, diluted in a little cold water, cut into large pieces potatoes, peeled garlic cloves, bay leaf, parsley and wine. Pour hot water, enough to cover the products close the pot and boil for 15-20 minutes.