Season the reserved raw chicken with salt and pepper and place in the skillet with the reserved oil, browning on each side but not cooking it through.
Add the diced onion to the oil and cook until browned, then add the brandy and reduce for a minute. Add the grated tomato pulp, discarding the juice, and simmer on low until the mixture is thickened but not dry, about 20 minutes.
Deglaze the tomato and onion mixture with some of the chicken stock.
Transfer the mixture into a large pot and add the browned chicken. Cover the chicken with the rest of the stock. (If there is still meat exposed, cover with extra water or fish bouillon.) Simmer uncovered on low heat for about 1 hour.
During the last 15 minutes of cooking, add the picada mixture (the almond, garlic, and bread paste).
After an hour of cooking, remove the chicken from the sauce and set aside on a large serving plate. If the sauce is too thin, turn up the heat for about 10 minutes so that some evaporates.
While the sauce is cooking down, add the shrimp and langoustines and cook for a couple of minutes, then remove them and reserve them with the chicken. Taste the sauce and add salt and pepper as desired.
Spoon the sauce over the chicken and shrimp on the serving plate. Serve alongside fried or boiled potatoes and enjoy!