Peel the onion and cut it in half.
Trim the celery stalk and cut it into 4 sections.
Peel the potatoes, rinse them, and place in a saucepan with the onion, celery, dill stalks (reserving the leaves), Espelette pepper, and saffron filaments wrapped in cheesecloth.
Cover with cold water, bring to a boil, and cook for 20 to 30 minutes until tender.
Remove the aromatics and saffron, then mash the potatoes with a potato masher or fine-grid vegetable mill for the silkiest results.
Incorporate the butter in pieces, followed by the cream, mixing gently to emulsify.
Reheat gently over low heat in a bain-marie to preserve the flavors.
Garnish with dill sprigs and a sprinkle of fleur de sel. Serve immediately for peak indulgence.
