Polenta Casserole with Mushrooms and Sun-dried Tomatoes

Using instant polenta significantly reduces the cooking time for this casserole thats loaded with Mediterranean flavors. 

5 from 1 vote
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Polenta Casserole with Mushrooms and Sun-dried Tomatoes

Prep Time30 mins
Cook Time20 mins
Course: Main Course
Servings: 9
Calories: 279kcal
Author: Gluten Free & More


  • 2 tablespoons (30 g) unsalted butter, plus more for greasing the pan
  • 4 cups (.9 L) water
  • 1 cup (236.6 mL) whole milk
  • 2 teaspoons (12 g) kosher salt, divided
  • 1 cup (122 g) instant polenta
  • ½ cup (24 g) thinly sliced green onions
  • 1 cup (100 g) grated Parmesan cheese, divided
  • 2 tablespoons (30 mL) extra virgin olive oil
  • 1 cup (115 g) diced sweet onion
  • 4 ounces (113 g) cremini mushrooms, sliced
  • 1 tablespoon (15 g) minced garlic
  • 1 tablespoon (1.7 g) fresh thyme leaves
  • 1 cup (175 g) sun-dried tomatoes in olive oil, drained and roughly chopped
  • 1 tablespoon (15 mL) tomato paste
  • 1 cup (236.6 mL) dry white wine
  • 4 cups (120 g) baby spinach, roughly chopped
  • ½ cup (15 g) fresh basil, chopped
  • 4 ounces (113 g) goat cheese, crumbled


  • Preheat the oven to 400°F and lightly grease a 9x13 baking dish with butter.
  • Combine the water and milk in a large saucepan and bring to a low boil. Stir in 1 teaspoon of salt. Reduce the heat to low, then gradually pour in the polenta in a steady stream while stirring constantly. Cook, stirring often, until the polenta has thickened, about 3 minutes. Remove the pot from heat, then stir in the butter, green onions, and ½ cup Parmesan cheese. Pour the polenta into the baking dish and spread it out in an even layer.
  • Meanwhile, heat the olive oil in a large skillet over medium-high heat. Add the onion, mushrooms, and the remaining teaspoon of salt. Cook until the onion is tender and the mushrooms have released their liquid, about 7-8 minutes.
  • Add the minced garlic and thyme and cook until fragrant, about 30 seconds.
  • Add the tomatoes to the skillet and cook for 2-3 minutes. Stir in the tomato paste and cook until it has slightly browned. Pour in the wine and deglaze the pan, scraping up any brown bits with a spoon. Simmer until the wine has reduced by about half, about 5 minutes. Add the spinach and cook until it has wilted, about 4-5 minutes. Stir in the basil, then remove the skillet from heat.
  • Layer the tomato and mushroom mixture on top of the polenta in the baking dish. Crumble in the goat cheese and sprinkle the remaining ½ cup of Parmesan on top.
  • Transfer the dish to the oven and bake for 25-30 minutes until the cheese has melted. Allow to rest for 5 minutes before cutting into squares and serving.


Nutrition Facts
Polenta Casserole with Mushrooms and Sun-dried Tomatoes
Amount Per Serving
Calories 279 Calories from Fat 117
% Daily Value*
Fat 13g20%
Saturated Fat 6g30%
Trans Fat 0.1g
Polyunsaturated Fat 1g
Monounsaturated Fat 5g
Cholesterol 23mg8%
Sodium 800mg33%
Potassium 715mg20%
Carbohydrates 27g9%
Fiber 3g12%
Sugar 8g9%
Protein 12g24%
Vitamin A 1924IU38%
Vitamin C 13mg16%
Calcium 234mg23%
Iron 2mg11%
* Percent Daily Values are based on a 2000 calorie diet.
Disclaimer: All nutrition facts on Gluten Free & More are meant only as a guide and may differ depending on product brands used or ingredient substitutions. Some errors may occur, so you are encouraged to confirm the recipe’s ingredient and nutrition suitability for your own diet.
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Tags: Casserole Mushrooms Polenta Tomatoes
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