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Portobello Penne Pasta Casserole

Portabello mushrooms, spinach, cheeses and penne combine to make a delicious casserole dish - perfect for family dinners or a party.
Print Recipe
Prep Time 15 minutes
Cook Time 30 minutes
Total Time 45 minutes
Course lunch/dinner
Cuisine Italian
Servings 8 people
Calories 4113.4 kcal

Equipment

  • 1 Large Stockpot For cooking pasta.
  • 1 Large Saucepan For sautéing mushrooms and preparing the cheese sauce.
  • 1 9x13 inch Baking Dish For assembling and baking the casserole.
  • 1 Whisk Essential for a smooth roux and lump-free cheese sauce.
  • 1 Wooden Spoon or Spatula For stirring and combining ingredients.

Ingredients
  

Main

  • 1 8 ounce package uncooked penne pasta
  • 2 tablespoons vegetable oil
  • ½ pound portobello mushrooms thinly sliced
  • ½ cup margarine
  • ¼ cup all-purpose flour
  • 1 large clove garlic minced
  • ½ teaspoon dried basil
  • 2 cups milk
  • 2 cups shredded mozzarella cheese
  • 1 10 ounce package frozen chopped spinach, thawed
  • ¼ cup soy sauce

Instructions
 

  • Preheat oven to 350 degrees F (175 degrees C). Lightly grease a 9x13 inch baking dish.
  • Bring a large pot of lightly salted water to a boil. Place pasta in the pot, cook for 8 to 10 minutes, until al dente, and drain.
  • Heat the oil in a saucepan over medium heat. Stir in the mushrooms, cook 1 minute, and set aside. Melt margarine in the saucepan. Mix in flour, garlic, and basil. Gradually mix in milk until thickened. Stir in 1 cup cheese until melted. Remove saucepan from heat, and mix in cooked pasta, mushrooms, spinach, and soy sauce. Transfer to the prepared baking dish, and top with remaining cheese.
  • Bake 20 minutes in the preheated oven, until bubbly and lightly brown.

Notes

To elevate this casserole, I recommend substituting margarine with unsalted butter for a richer, more nuanced roux; cook the flour for at least 2 minutes to remove any raw taste. When sautéing portobello mushrooms, ensure your pan is hot and avoid overcrowding to achieve proper caramelization, enhancing their earthy notes. Thoroughly squeeze excess water from the thawed spinach to prevent a watery casserole base. For a brighter profile, consider adding a teaspoon of Dijon mustard or a splash of dry white wine to the cheese sauce, complementing the soy sauce and balancing the richness. Use freshly shredded mozzarella for optimal melt and texture. Always cook pasta al dente, as it will finish cooking in the oven, preventing it from becoming mushy.