Step by step recipe:

1. 15 min.
   Prepare 800 g potimarron (Japanese chestnut pumpkin) and cut into medium-sized chunks.
   
   Set aside.
2. 15 min.
   Prepare 400 g leeks and chop finely.
   
   Set aside.
3. 4 min.
   Prepare 50 g onion and chop finely.
   
   Set aside.
4. 1 min.
   Pour 4 tablespoons olive oil into a large saucepan on high heat. When good and hot, add the chopped onion, salt and pepper.
   
   Cook for 1 minute without colouring.
5. 3 min.
   Add the pumpkin and leeks to the pan, salt and pepper again, then mix well.
   
   Cook for 2 or 3 minutes, stirring frequently.
6. 1 min.
   Pour in 1 litre whole milk (1 pint 3/4) and mix well.
7. 25 min.
   Leave to simmer on low heat until the pumpkin is soft.
8. 3 min.
   Blend thoroughly until the soup is completely smooth.
9. 
   Check the seasoning before serving.