Cook the mushrooms:
Place a skillet on the stovetop over medium-high heat. Once hot, add the mushrooms and cook for 8–10 minutes. They will release a lot of moisture, which will evaporate, allowing them to take on a deep golden color. Season all over with salt and pepper.
Sauté the zucchini and onion:
Pat the zucchini dry and discard the paper towels.
Pour the olive oil into the skillet with the mushrooms and toss to coat the mushrooms in the oil briefly. Add the onion and sauté for 5 minutes. Add the zucchini and sauté for 3–4 minutes over medium-high heat until the zucchini softens.
Reduce the heat to low and stir in the butter and parsley. Cook for 3–4 minutes until the onion and zucchini are softened and glossy. Season with salt and pepper.
Calories: 81kcal | Carbohydrates: 6g | Protein: 3g | Fat: 6g | Saturated Fat: 1g | Sodium: 53mg | Fiber: 2g | Sugar: 4g