Preheat the oven to 180°c.
Heat the olive oil in a large, shallow ovenproof pan. Add the chicken pieces and brown for a few minutes on each side until golden, then set aside.
In the same pan, fry the onion for a few minutes, scraping up the bits stuck to the bottom. Add the garlic, chorizo and peppers, and fry for several minutes until the chorizo releases its red oil.
Stir in the paprika and chilli flakes.
Turn the heat to low and add the rice, stirring to coat every grain in the flavoured oil.
Slowly pour in the chicken stock. Don't add it all, as the level will rise when the chicken goes back in. Hold some back to top up later if needed.
Nestle the chicken pieces back into the pan, leaving the skin exposed so it crisps. Season with salt and pepper.
Bake for 45 to 50 minutes, until the chicken is crisp on top and the rice has absorbed the stock and is soft, a bit like a risotto. Add a splash more stock during cooking if it looks dry.
Squeeze lemon juice over the top and scatter with fresh parsley before serving.