In a medium bowl, mix the feta with ¼ teaspoon of the chilli flakes, 2 teaspoons of the fennel seeds and 1 tablespoon of the oil. Set aside while you cook the orzo.
Place a large sauté pan, for which you have a lid, on a medium high heat. Add 2 tablespoons of oil, orzo, ⅛ teaspoon of salt and a good grind of pepper. Fry for 3–4 minutes, stirring frequently, until golden-brown, then remove from the pan and set aside.
Return the pan to the same heat and add the remaining 2 tablespoons of oil, ¼ teaspoon of chilli flakes and 2 teaspoons of fennel seeds, the garlic and the orange skin.
Fry for 1 minute, until the garlic starts to lightly brown, then add the tomatoes, stock, 200ml of water, ¾ teaspoon of salt and plenty of pepper. Cook for 2–3 minutes, or until boiling, then stir in the fried orzo. Cover, then lower the heat to medium low and leave to simmer for 15 minutes, stirring once or twice throughout so the orzo is cooked.
Remove the lid and cook for a further 1–2 minutes, until the consistency is like a risotto. Stir in the prawns for 2–3 minutes until they are pink and cooked.
Stir in the basil and serve at once, with the marinated feta sprinkled on top.
