Portobello Penne Pasta Casserole

Ingredients

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