Step by step recipe:

1. 10 min.
   Prepare 250 g leek and chop finely.
   
   Set aside.
2. 5 min.
   Dice 250 g cooked chicken.
   
   Preheat the oven to 360°F (180°C).
3. 5 min.
   Prepare 1 shallot and 1 onion.
   
   Chop both, but the shallot very finely.
4. 2 min.
   Use a large pan that can go both on the hob and in the oven. Melt 20 g goose fat on medium heat. When good and hot, add the chopped onion.
   
   Salt and pepper, then cook without colouring while stirring for 1 or 2 minutes.
5. 1 min.
   Tip in 300 ml rice all at once and cook while stirring for about 1 minute.
6. 
   The rice should "pearl" (become translucent).
7. 2 min.
   Pour in 450 ml poultry cooking juices and mix briefly.
8. 20 min.
   Cover with aluminium foil (or an oven-proof lid) and cook in the oven for 20 minutes.
9. 1 min.
   While the rice is cooking, pour 2 tablespoons olive oil into a large frying pan on medium heat. When hot, add the chopped shallot, salt and pepper, then cook for 1 minute without colouring.
10. 5 min.
    Add the chopped leeks, mix well and cook until the leeks are just tender but still nice and green (about 4 or 5 minutes).
11. 2 min.
    Add the diced chicken, mix well, salt and pepper again, then check the seasoning.
    
    Leave to heat through for 1 or 2 minutes, then turn off the heat.
12. 3 min.
    When the rice is cooked, take it out of the oven and add the chicken and leek mixture. Mix well.
13. 
    Serve piping hot.