Clean mushrooms and cut into halves or quarters if large.
1 pound (16 oz.) mushrooms
Heat 2 tablespoons of oil in a large skillet over high heat. Add mushrooms, sprinkle with salt and pepper, and cook, stirring occasionally (not constantly!), until they are golden brown and starting to release liquid, 3 to 4 minutes. Remove mushrooms from pan, place in a bowl, and set aside.
3 tablespoons olive oil, divided, ½ teaspoon kosher salt, ¼ teaspoon coarse ground black pepper
Add remaining 1 tablespoon oil to pan and reduce heat to medium. Add onion and garlic, and cook, stirring frequently, for 2 to 3 minutes or until onions are soft and translucent.
½ cup diced onion, 3 cloves garlic, minced
Add heavy cream, sun dried tomatoes, and oregano. Bring to a simmer and cook for 1 to 2 minutes or until starting to thicken.
1 cup heavy cream, ¼ cup sun dried tomatoes packed in oil, drained (reserve oil!), patted dry, chopped, ¼ teaspoon dried oregano
Reduce heat to medium-low, add spinach, and cover. Cook with lid on for 2 to 3 minutes or until the spinach has wilted, stirring once or twice if needed.
5 ounces baby spinach, roughly chopped
Stir in cheese and mushrooms and cook for another 2 to 3 minutes or until the sauce has desired consistency.
1 cup shredded Parmesan cheese, lightly packed
Stir in basil and serve as desired. See notes for suggestions.
6 to 8 fresh basil leaves, chopped
Video
Notes
Storage & reheating: Leftover Tuscan mushrooms can be refrigerated for up to three days. To reheat, warm the mushrooms in a skillet over low heat. Try not to overheat or boil the mushrooms because the creamy sauce may curdle at high heat. They can be reheated in the microwave as well.
Sun-dried tomatoes: If using sun-dried tomatoes that are not packed in oil, soak them in water before draining and patting dry. Refer to the package of sun-dried tomatoes for directions.
Serving suggestions: Serve with pasta, rice, or bread, or as a side for steaks, chicken, or pork.