In medium pot, bring stock and milk to a low, rolling boil and whisk in a single direction while pouring polenta in slowly. Add pepper and a few grates of nutmeg, and bring to a bubble. Reduce heat to a simmer to keep the mix at a delayed bubble, a burp every 2 seconds or so. Cook 45 minutes, whisking every 10 minutes or so. Stir in butter, honey and cheese, and remove from heat; season with salt to taste. Keep warm in a bain marie while you cook the mushrooms and make the salad.
To make a Bain Marie, use a pot that is wide enough to fit your polenta pot comfortably inside it, a wide pan a few inches deep will do. Place about 3/4 inch of water in the wider pan. Bring water to a gentle simmer and keep simmering over medium-low flame, adding more water if necessary until ready to serve.