Ingredients

For the Polenta

• 320 g / about 2 cups coarse yellow polenta cornmeal Use traditional, non-instant polenta for the fullest flavor and texture.
• 1.5 liters / about 6⅓ cups water
• 1½ teaspoons fine sea salt
• 30 g / 2 tablespoons unsalted butter
• 70 g / about ¾ cup finely grated Parmigiano-Reggiano

For the Mushrooms

• 30 g / about 1 ounce dried porcini mushrooms
• 500 g / about 1 pound mixed fresh mushrooms Cremini, oyster, shiitake, chanterelle, or fresh porcini may be combined.
• 2 tablespoons extra-virgin olive oil
• 15 g / 1 tablespoon unsalted butter
• 2 garlic cloves, lightly crushed
• 2 tablespoons finely chopped flat-leaf parsley, plus more for serving
• ½ teaspoon fine sea salt, plus more as needed
• Freshly ground black pepper
• Warm water or light vegetable broth, as needed

For Serving

• Additional finely grated Parmigiano-Reggiano
• Extra-virgin olive oil, optional

Preparation

1. Rehydrate the porcini. Place the dried porcini in a bowl and cover with about 1 cup of warm water. Let them stand for 20 minutes. Lift them from the liquid, rinse briefly to remove grit, squeeze gently, and chop. Strain the soaking liquid through a coffee filter or several layers of cheesecloth and reserve it.
2. Begin the polenta. Bring the water and 1½ teaspoons salt to a boil in a heavy saucepan. Reduce to a steady simmer and pour in the cornmeal in a thin stream while whisking continuously.
3. Cook slowly. Switch to a sturdy wooden spoon. Cook over low heat for 45–50 minutes, stirring frequently and scraping the bottom and corners. The polenta should become tender, creamy, and pull slightly from the sides of the pan.
4. Prepare the fresh mushrooms. While the polenta cooks, clean the fresh mushrooms with a brush or lightly damp towel. Trim the stems as needed and cut the mushrooms into substantial slices or pieces.
5. Brown in batches. Heat the olive oil in a wide skillet over medium-high heat. Add the crushed garlic. Cook the fresh mushrooms in two or three batches so the pan does not become crowded. Let each batch brown before stirring frequently.
6. Add the porcini. Return all fresh mushrooms to the skillet and add the chopped porcini. Pour in ¼ cup of the strained porcini liquid and simmer until the mushrooms are tender and the liquid has reduced to a glossy coating.
7. Finish the mushrooms. Season with salt and black pepper. Remove the garlic cloves, stir in the tablespoon of butter and chopped parsley, and take the pan off the heat.
8. Finish the polenta. Remove the cooked polenta from the heat and stir in the butter and Parmigiano-Reggiano. When the polenta is too firm to flow softly from the spoon, loosen it with a little hot water or broth.
9. Assemble the dish. Spoon the hot polenta into warm shallow bowls or onto a serving platter. Create a shallow well in the center and add the mushrooms with their pan juices.
10. Serve immediately. Finish with Parmigiano-Reggiano, parsley, black pepper, and a small drizzle of olive oil when desired. Serve while the polenta remains soft and flowing.