Clean and slice the 1 lb mushrooms, setting them aside.
In a bowl, combine 4 tablespoons butter, 4 tablespoons margarine, 1/4 cup chopped onion, 2 teaspoons beef base, 1 teaspoon garlic powder, 1 teaspoon black pepper, and 1 cup red Burgundy wine. Mix until well combined.
Add the sliced mushrooms into the bowl with the sauce mixture and toss to coat evenly.
Set the air fryer to 375°F (190°C) and preheat for 3-5 minutes.
Place the coated mushrooms in the air fryer basket in a single layer. Air fry for 8-10 minutes, shaking the basket halfway through.
Once the mushrooms are tender and caramelized, remove them from the air fryer.
Transfer the mushrooms to a serving dish and enjoy as a side dish or topping for steak!