- 1 (16 ounce) tube prepared plain polenta, sliced into rounds
- 1 tablespoon extra-virgin olive oil
- 1/2 cup minced onion
- 1 pound mushrooms, such as white or cremini, sliced
- 2 cups stemmed and sliced shiitake mushrooms
- 1/4 teaspoon salt
- 1/4 teaspoon freshly ground pepper
- 1/2 cup white wine
- 1/2 cup reduced-fat sour cream
- 2/3 cup shredded fontina cheese (see Note)
- 2 teaspoons minced fresh tarragon
- Preheat oven to 400 degrees F. Coat a baking sheet with cooking spray.
- Arrange the polenta on the prepared baking sheet and bake until crispy on the bottom and heated through, about 20 minutes.
- Meanwhile, heat oil in a large skillet over medium-high heat. Add onion and cook, stirring often, until lightly browned, 2 to 3 minutes. Stir in mushrooms, salt and pepper, and cook, stirring often, until the mushrooms are softened and most of the liquid has evaporated, 8 to 10 minutes.
- Pour in wine; bring to a boil and scrape up any browned bits from the bottom of the pan. Reduce the liquid until the pan is almost dry, 2 to 3 minutes. Stir in sour cream and bring to a simmer. Remove from the heat, stir in cheese and tarragon. Serve the sauce over the polenta.