Heat olive oil in a wide pan. Gently cook onion with a pinch of salt until soft and sweet, around 5-7 minutes. Add garlic, oregano and chilli, cook until fragrant.
Stir in tomato paste and let it cook out properly so it darkens slightly. Pour in white wine and reduce by half so it turns slightly syrupy and sharpens the base. Add crushed tomatoes and simmer for 5 to 10 minutes until it thickens slightly. Add prawn stock and bring everything to a steady simmer.
Stir in orzo and cook gently, stirring often, like a loose risotto. When the orzo is almost cooked, add prawns and fold through until just cooked through and opaque. Turn off the heat. Crumble in half the feta so it melts slightly into the sauce, then finish with the rest on top for texture.
Finish with parsley, lemon juice, and a final drizzle of olive oil.
