Step 1 In a medium, heavy-bottom saucepan, combine the cream and milk and bring to a simmer. Slowly whisk in the polenta and reduce the heat to low. Cook, stirring every few minutes or so, making sure to scrape the bottom of the pan so the polenta does not burn. Cook the polenta until it is creamy, about 30 minutes, adding additional milk if the polenta thickens too quickly before it is tender. Remove from heat, cover and set aside for 20 to 30 minutes.
Step 2 Whisk in the butter and grated cheese, then taste and adjust the seasonings with salt and pepper.