How to make
Peel and cut the celery head into cubes. Peel and slice the potatoes.
Put them in a pot, pour about 4 cups (1 liter) of water and season with salt. Boil, until the vegetables soften.
Strain and mash them with a vegetable press while they are warm.
Add the butter and milk. Season with a pinch of nutmeg.
Stir with a wire whisk (not with a mixer, because it will turn into a sticky mixture), until you get a fluffy and smooth puree.
Pour it into a plate and decorate it with celery leaves and olives!
The celery and potato puree is ready.