I think this is the Eerligh special, built by a man named Eerligh on Fiat 1100 base.
According to the information I received, this car is indeed equipped with a Fiat 1100 engine, but it is based on a Fiat Topolino:
EerlichIn June 1951, Eerligh appeared with a home-build car at sport car races. The racecar was based on the chassis of a Fiat Topolino. Instead of the 500 cc engine, a Fiat 1100 cc engine was built in. The beautifully finished carbody had rounded lines and integrated mudguards. Eerligh did not participate in races for a long time. Later on, Han van Pelt drove with the car.
And a picture of the car with what I think is the original grille