The shrimp are cleaned of the crust. Cut the core into small cubes and season with salt and pepper, and set aside the crusts until we use them.
Carrot, onion and garlic cut into larger cubes and fry in 3-4 tablespoons of olive oil, not until golden brown but until the onion becomes transparent. Then add the shrimp crusts, paprika, bay leaf, tomato paste and wine, mix well. Leave it for another 3-4 minutes then add water, about 1.7 liters and let it boil for 30 minutes over medium heat.
In the meantime, the croutons can be made: the bread is broken / cut into small cubes and "dressed" well in olive oil, put in a tray on baking paper and put in the oven until browned.
Add flour over the soup (if you want you can dissolve it in a little water first) and let it boil for another 5 minutes until it thickens, then pass everything through a sieve. Put the liquid back on the fire and add the diced shrimp core. Add a little more salt and pepper and let it boil for about 5 minutes.
Serve the soup and croutons together.