1. In a large pot over medium heat bring the stock to the boil.
2. Slowly, whisk in polenta. Cook, stirring, for 2-3 minutes, or until it becomes thickened.
3. Turn off the heat. Then, add the butter, parmesan, herbs, salt, and black pepper. Mix well.
4. Transfer into a lightly greased 9†x 13†(23 x 33 cm) baking pan and spread to make 1/2-inch (1-cm) thick. Place in the fridge for at least 1 hour.
5. Preheat your air fryer to 400 F (200 C).
6. Cut the prepared polenta into 1/2†x 4†(2 x 10 cm) stick and spray lightly with oil.
7. Place on the air fryer cooking basket, and cook for 20 to 25 minutes, turning halfway through cooking, until golden and crisp.