Ingredients :

• Tête de Moine AOP — This is the Swiss cheese that is shaved into rosettes with a ‘girolle’, a tool with a rotating blade. Many cheese shops offer ready-to-use rosettes — convenient and impeccable. Its character is bold: herbal, slightly spicy, with a paste that melts quickly. The AOP label is important; imitations lack the same complexity. If you really can’t find it, finely grated Swiss Emmental can work for the filling, but forget about the rosettes.
• Vacuum-packed cooked beetroot — Get the one from the vegetable section in the supermarket, plain vacuum-packed beetroot. Absolutely not the jarred beetroot preserved in vinegar — too acidic, it would throw off the whole filling. Homemade roasted beetroot gives even more character, but vacuum-packed works very well.
• Full-fat Greek yogurt — It entirely replaces mayonnaise here. Get the full-fat version — 0% makes a filling that is too liquid and lacks structure. Its natural acidity balances the sweetness of the beetroot without needing to overdo the lemon.
• Cider vinegar — Marked as optional in the recipe, but don’t skip it. A teaspoon is what gives that little kick of liveliness at the finish — without it, the filling stays just a bit too sweet.