Prep the turnips: Peel and cut turnips into even 1-inch cubes. Rinse and pat them very dry. Drying helps them crisp instead of steam.

Preheat the air fryer: Set to 390°F (200°C) for 3–5 minutes. A hot basket gives better browning.

Season for the first cook: In a bowl, toss turnips with 1–1.5 tablespoons olive oil, 1/2 teaspoon salt, 1/4 teaspoon black pepper, and 1/2 teaspoon garlic powder.

Air fry the turnips: Spread in a single layer in the basket (work in batches if needed). Cook 12–15 minutes, shaking halfway, until fork-tender with light browning.

Make the glaze: While turnips cook, melt 1 tablespoon butter in a small saucepan over low heat. Stir in 1 tablespoon honey or maple syrup, 1 teaspoon Dijon, and 1 teaspoon apple cider vinegar or lemon juice. Simmer 30–60 seconds until slightly glossy. Taste and adjust sweetness or tang.

Toss with glaze: Transfer cooked turnips to a bowl and pour the glaze over. Toss to coat evenly. If using red pepper flakes, add a pinch now.

Finish in the air fryer: Return glazed turnips to the basket in a single layer. Air fry 3–5 minutes more at 390°F until the glaze caramelizes and edges crisp. Watch closely to avoid scorching.

Season and serve: Taste and adjust salt. Sprinkle with fresh thyme or parsley and a crack of pepper. Serve hot.