Heat the Butter: In a large skillet, melt the butter over medium heat. Once melted, allow it to slightly brown for a nutty flavor.

Cook the Onions: Add the sliced onions to the skillet. Sauté for 5–7 minutes, stirring occasionally, until the onions become soft and start to caramelize.

Add Garlic and Mushrooms: Stir in the minced garlic and cook for 1 minute until fragrant. Add the mushrooms to the skillet and toss to coat them in the butter mixture.

Deglaze with White Wine (Optional): If using white wine, pour it into the skillet, scraping up any browned bits from the bottom. Let it simmer for 2–3 minutes, allowing the wine to reduce slightly.

Add Soy Sauce: Drizzle the soy sauce over the mushrooms and onions. Stir well to combine, and cook for another 5–7 minutes, or until the mushrooms are tender and golden.

Finish with Parsley: Remove the skillet from heat and sprinkle the dish with fresh chopped parsley for a burst of color and freshness.

Serve: Serve hot as a side dish or topping for steaks, burgers, pasta, or rice.