Creating Garlic Butter Mushrooms and Onions with White Wine is simple and straightforward. Follow these steps to prepare this delectable side dish:

1. Prepare the Ingredients: Start by cleaning and slicing the mushrooms and onions. Mince the garlic and set aside.
2. Heat the Pan: In a large skillet, heat the olive oil and 1 tablespoon of the butter over medium heat.
3. Sauté Onions: Add the sliced onions to the pan and sauté until they become translucent, about 3-5 minutes.
4. Add Garlic: Once the onions are softened, add the minced garlic and sauté for another minute until fragrant.
5. Add Mushrooms: Incorporate the sliced mushrooms into the skillet. Stir occasionally, cooking until they are tender and lightly browned, approximately 5-7 minutes.
6. Deglaze with White Wine: Pour in the white wine, scraping any bits stuck to the bottom of the pan. This will add depth to the flavor. Allow it to simmer for 2-3 minutes.
7. Finish with Butter: Stir in the remaining 2 tablespoons of butter until melted, creating a rich, creamy sauce.
8. Season: Season with salt and pepper to taste. Adjust as necessary.
9. Garnish: If desired, sprinkle chopped fresh parsley over the top just before serving for a fresh touch.
10. Serve Warm: Transfer the garlic butter mushrooms and onions to a serving dish and enjoy.

With these simple steps, you will have an incredible side dish ready in no time!