Ingredients:
- 6 cups chicken stock, plus more if needed
- 2 1/2 cups coarse polenta
- Salt and coarse black pepper
- Salt and coarse black pepper
- 6 tablespoons butter, plus more for dotting casserole
- 1/2 cup dried porcini mushrooms (a couple of handfuls)
- About 1/3 cup EVOO
- 1 1/2 pounds cremini or white mushrooms, sliced
- 2 tablespoons finely chopped fresh thyme
- 2 shallots, finely chopped
- 1/2 cup dry white wine or 1/4 cup Marsala or sherry
- 2 cloves garlic, grated
- 1/4 cup flour
- 2 1/2 cups milk
- Freshly grated nutmeg, as needed
- 1 1/2 cups grated Parmigiano-Reggiano