The next time you make gnocchi save the left over potato skins and make this consommé while they are hot
Thinly slice the two leeks seperating the white of the leek from the green. Sweat the white of the leek only in butter with salt and pepper until tender
Once tender add 10 of the hot potato skins to pan stirring into the leeks. Allow to cook out for 2 minutes then add the nage
Bring the nage to the boil skimming constantly. As soon as the soup reaches the boil drop to a simmer and leave for 20 minutes
After the 20 minutes skim once again and remove from the heat. Add the kombu, thyme and bay, cover the saucepan tightly with clingfilm and set aside to infuse for 2 hours.
After the soup had infused for 2 hours pass through a chinois into a tall heavy bottomed pot and place back on the stove
Now add the 2 remaining potato skins along with green leek and egg white to a thermomix blender and blitz on full for 1 minute until a slurry is formed
Once the soup on the stove has reached 60°c whisk in the leek and potato slurry. Drop the heat to a moderate temperature
After 15 minutes or so a stable raft should have floated to the top of the soup bring all the debris and impurities with it. Carefully make a hole in the raft as you will need this to extract the consommé later
Leave the soup to clarify for a further 30 minutes. Once you are happy with clarity of the soup you can extract it from the hole in the raft using a ladel. Pass through muslin cloth and re-season
The consommé is now ready