Step 1

Place sweet potato in basket of the air fryer. Heat to 180°C. Spray with oil and sprinkle with salt. Cook, turning halfway, for 20 minutes or until crisp. Set aside and keep warm.

Step 2

Meanwhile, combine the crème fraîche, milk, horseradish, tarragon and shallot in a bowl. Season.

Step 3

Place the steaks in the basket. Cook, turning halfway, for 10 minutes. Transfer steaks to a plate, cover with foil and set aside for 5 minutes to rest.

Step 4

While the steaks are resting, place the mushrooms, base-side up, in the air fryer basket. Sprinkle with extra tarragon. Spray with oil and place the butter on the gills of the mushrooms. Cook for 5 minutes.

Step 5

Divide the sweet potato, mushrooms and steak between serving plates. Drizzle with crème fraîche mixture. Serve with watercress.