Baked Mushrooms and Polenta Gratin

1 . Stage

Preheat the oven to 350 degrees F (175 degrees C). Butter an 8x12-inch baking dish.

2 . Stage

Bring water and 1 teaspoon salt to a boil in a medium saucepan. Add cornmeal in a slow stream, whisking. Whisk in 1 tablespoon oil and ¼ teaspoon sage. Reduce the heat and simmer, stirring frequently with a wooden spoon, until very thick, about 20 minutes. Stir in 3 tablespoons Parmesan cheese.

3 . Stage

Meanwhile, melt 1 tablespoon butter with 1 tablespoon oil in a large frying pan over medium-high heat. Add 1/2 of the mushrooms, ¼ teaspoon of each of the salt and sage, and 1/8 teaspoon of the pepper. Cook, stirring frequently, until mushrooms are golden, about 5 minutes. Remove. Repeat with remaining mushrooms, 1 tablespoon each butter and oil, ¼ teaspoon salt and sage and 1/8 teaspoon black pepper.

4 . Stage

Pour 1/2 of the polenta into the prepared baking dish and spread in an even layer. Top with 1/2 of the mushrooms, followed by 1/2 of the Fontina cheese and 2 tablespoons Parmesan cheese. Repeat with remaining polenta, mushrooms, Fontina and Parmesan cheeses.

5 . Stage

Bake in the preheated oven until cheese is bubbling, about 15 minutes.