In a large, heavy saucepan, bring water to a boil and season with salt.
Peel the celery and cut it into cubes. Pour into boiling water, let the water boil again. Reduce heat, simmer celery until soft, about 20 minutes.
Throw the celery into a colander, let the water drain. Then transfer the celery to a large bowl.
Immediately put the saucepan on medium heat, melt the butter in it. Pour in chopped garlic, cook over low heat for a couple of minutes. Put boiled celery in a saucepan, stir, kneading slightly with a spoon, cook for about 5 minutes.
Remove the pot from the stove, add broth or water to the celery, and add additives to taste. Then puree the celery with a potato grinder or blender. Add salt and pepper to taste.