Creamy Baked Polenta and Mushrooms

Butter a 8x12-inch rimmed baking sheet. Bring water to a boil in a saucepan. Add cornmeal and whisk. Cook until mixture pulls away from the sides of the saucepan, stirring constantly, 5 to 7 minutes.

Stir in 1/4 cup Parmesan cheese, egg yolk, 2 tablespoons melted butter, salt, and nutmeg. Pour onto the prepared baking sheet and spread into a rectangle about 1/2 inch thick. Cool for at least 2 hours. Trim edges and cut into 1-inch cubes.

Heat olive oil and 1 tablespoon butter in a skillet over medium-high heat. Add onions and saute for 5 minutes. Add mushrooms and cook for 5 minutes. Stir in brandy and garlic; heat through, about 5 minutes more. The mixture should be saucy.

Preheat the oven to 400 degrees F (200 degrees C). Butter a large baking dish.

Place polenta cubes in the prepared baking dish, top with mushroom mixture, including juices. Mix remaining 1/4 cup Parmesan cheese, remaining 2 tablespoons melted butter, bread crumbs, and dried parsley together in a bowl. Sprinkle bread crumb mixture on top of mushrooms.

Bake in the preheated oven until browned and bubbly, about 30 minutes.