Prep the cauliflower: Rinse and thoroughly dry the florets. Drying helps the marinade stick and ensures crisp edges.
Make the marinade: In a large bowl, whisk yogurt, lemon juice, tandoori masala, cumin, coriander, turmeric, chili powder, garlic, ginger, oil, and salt until smooth.
Coat the florets: Add cauliflower to the bowl and toss to coat evenly.
The florets should be well covered but not dripping. Let it sit for 10–20 minutes while you heat the air fryer.
Preheat the air fryer: Set to 390°F (200°C) for 3–5 minutes. Preheating promotes better browning.
Load the basket: Lightly spray the basket with oil.
Arrange the cauliflower in a single layer. Do not overcrowd; cook in batches if needed.
Air fry: Cook at 390°F (200°C) for 12–15 minutes, shaking the basket halfway. The florets should be charred in spots and fork-tender. If needed, add 2–3 more minutes.
Make the mint yogurt: While the cauliflower cooks, blend yogurt, mint, cilantro, garlic, lemon juice, cumin, salt, and pepper until smooth.
Adjust lemon and salt to taste. For a thicker dip, use Greek yogurt.
Finish and serve: Transfer hot cauliflower to a platter. Sprinkle with cilantro or mint, add red onion if you like, and serve with lemon wedges and the mint yogurt on the side.