Preheat the oven to 300 degrees with the rack positioned in the lower half of the oven. Bring 3 cups of water to a boil over high heat. Place the polenta and salt in a 2-quart oven-safe casserole dish and whisk in the beer until smooth. Whisk in the boiling water until the polenta is smooth. Cover the dish with a tight-fitting lid or foil and place in the oven to cook for 1½ to 2 hours, stirring every 30 minutes. When the polenta is swelled, glossy and pulls away from the sides of the pan when stirred, remove it from the oven and stir in the butter and Parmesan. Cover and keep warm until ready to serve.
Recipe by The Tennessee Magazine at https://www.tnmagazine.org/the-blarney-benefit-of-beer/