- Bring broth and salt to a boil in a large saucepan; pour polenta slowly into boiling broth (as is the polenta is raining), whisking constantly until all polenta is stirred in and there are no lumps.
- Reduce heat to low and simmer, whisking often, until polenta starts to thicken, about 5 minutes. Polenta mixture should still be slightly loose. Cook for 30 minutes, whisking every 3 to 5 minutes. Polenta is done when texture is creamy, and the individual grains are tender.
- When the polenta is cooked and thick; add cream and stir with a spoon.
- Turn off heat and gently stir butter into polenta until butter partially melts; mix Parmigiano-Reggiano cheese into polenta until cheese has melted, stir and taste for salt before plating into a serving bowl.