Ingredient:

• 1 tablespoon olive oil
• 1 yellow onion, sliced
• 8 ounces white mushrooms, sliced
• 2 cloves garlic, minced
• 1/4 teaspoon crushed red chile flakes
• 1 teaspoon kosher salt
• 4 cups chicken broth
• 8 ounces rotini pasta
• 1 (5 ounce) bag baby spinach
• 1/2 cup grated Parmesan cheese
• 1 teaspoon lemon juice