Rinse the green section of the leek (1 stalk). Once the surface has dried completely, cut into 5 mm pieces.

Put 100 ml of vegetable oil, the leek from Step 1, and the slice of ginger into a cool frying pan. Turn down the heat to very low and cook for 25 minutes.

Occasionally stir the pan.

When the time has passed, strain through a strainer and it's done.

Once cooled, pour into a jar with a lid.