When I was a kid it was a staple in our house on Friday because we were Catholic and couldn’t eat meat on Friday. We made it with melted butter, a large amount of garlic and anchovies. It was kept warm on the stove and we dipped lettuce, celery, cauliflower and bread in the mixture. It was fantastic. Have seen it, and have had it in old style Italian restaurants where there is a large Italian population.
Some people used to make it with a little cream added to it but we never did. By the way, the house smelled of garlic for a couple of days afterwards.