Wash and cut the cauliflower into bite-sized florets.

In a large bowl, mix together the flour, cornstarch, garlic powder, paprika, salt, and pepper.

Gradually add the plant-based milk or water to the dry ingredients, whisking until a smooth batter is formed.

Dip each cauliflower floret into the batter, ensuring it's well coated.

Shake off any excess batter.

Preheat your air fryer to 375°F (190°C).

Lightly grease the air fryer basket with oil.

Place the battered cauliflower in the basket in a single layer, ensuring they are not overcrowded.

Air fry for 20-25 minutes, flipping halfway through, until golden and crispy.

While the cauliflower is cooking, combine vinegar, sugar, ketchup, soy sauce, and pineapple juice (if using) in a saucepan.

Cook over medium heat, stirring until the sugar is dissolved and the sauce is heated through.

In a separate pan, sauté the bell pepper and onion until they are just tender.

Once the cauliflower is done, toss it with the sautéed vegetables and the sweet and sour sauce, ensuring everything is evenly coated.

Garnish with green onions and sesame seeds.

Serve hot, ideally with a side of rice or noodles.