Heat the oven to 325F and put a kettle on. Butter or oil four small ramekins.

Blend the ricotta, eggs, parmesan and salt for 30 seconds, until completely smooth. Ricotta stirred by hand stays slightly grainy in the finished custard.

Divide between the ramekins and set them in a deep baking dish.

Pour boiling water into the dish until it reaches halfway up the ramekins, taking care not to splash any into the custard.

Bake 30 to 35 minutes, until the edges are set and the centers still wobble slightly when nudged. They finish setting as they cool.

Lift the ramekins out of the water and cool at least 10 minutes before eating warm, or chill and eat cold.