Between 1664 and 1667, the Marquis Domenico Donato Del Carretto di Balestrino, lord of Bossolasco, had a new building built near the ruined castle and the parish church dedicated to San Giovanni Battista.

The new seventeenth-century building still exists today and is affectionately called Palazzone by the Bossolasco residents for its imposing size that distinguishes it from the nearby buildings. It overlooks Via Umberto I, once called Contrada del Poggio, which meant the height or crest of the hill, also called Via Principale or Via della Piazza (because it was the central street of the town and extended to Pian della Croce).

The stones used for the construction of the new building were partly recovered from the ruins of the ancient castle and partly collected in the bed of the Belbo stream. Externally, it appears as a massive and regular rectangular parallelepiped with exposed brickwork. The building consists of three floors above ground and a basement dug into the rock once used as a prison but now a cellar. The ground floor is characterized by an interesting entrance hall and an elegant grand staircase that leads to the first floor of the building, the piano nobile. The entrance hall, covered by a pavilion vault, is accessed through a wooden portal with studs framed by a series of raised bricks.

On the outside, the door is surmounted by a stylised eagle, in brick, symbol of the Marquises Del Carretto. The internal distribution of the rooms is typical of noble houses and palaces: the halls are arranged next to each other with the connecting doors aligned; the corridor, both on the ground floor and on the first floor, has a median position overlooking the secondary facade (south side) and contains the service staircase, in brickwork, which connects all the floors of the building.

The rooms on the first floor mostly have pavilion vaults apart from one room covered by a planetary vault. The palace belonged to the Del Carretto family of Balestrino until 1828, the year in which they sold it to the notary of Bossolasco Luigi Cabutti. Like the marquises, the notary and his descendants did not settle in the palace and continued to rent it to the community of Bossolasco and its district for the offices of the magistrate's court, for the archive, the district court, the prisons, etc. Finally, towards the middle of the twentieth century, some rooms on the ground floor housed the nursery and the elementary schools.