Prato, Tuscany. Cantucci (biscotti di Prato) are one of the most historically documented Italian biscuits — appearing in Florentine records from the 14th century. The Vin Santo pairing was established in the tradition of the Tuscan noble table.
Cantucci (incorrectly but universally called 'biscotti' outside Tuscany — biscotti means any biscuit in Italian) are twice-baked almond biscuits from Prato: logs of dough baked once until barely set, sliced diagonally, then baked again flat until the cut surfaces are golden and completely dry. The twice-baking creates the characteristic dense, crunchy texture that makes them inedible alone but perfect when dipped in Vin Santo. The almonds are whole, unblanched, and added raw — they toast during baking.
Alone, cantucci are almost unpleasantly hard with a dry, almond-and-sugar flavour. Dipped in Vin Santo — the aged, oxidised, slightly sweet wine — they soften in seconds to a crumbly, wine-soaked almond-bread texture. The wine's dried-fruit and nut flavours merge with the cantucci. The combination is designed — neither is complete without the other.
Dough: 00 flour, sugar, eggs (no fat — no butter, no oil), baking powder (or ammonia in the traditional Pratese version), and whole unblanched almonds. Mix to a stiff dough, form into logs, brush with egg wash, bake 180°C for 25 minutes until just set. Cool slightly (10 minutes) then slice at 45° into 1.5cm slices. Return cut-side down to baking tray and bake 180°C for a further 12-15 minutes until golden and completely dry. They should be rock hard when cooled. The absence of fat is the technical key — fat would shorten the texture; these must be hard.
The ammonia version (ammonio carbonato — baker's ammonia, not household ammonia) used in the original Pratese recipe gives a lighter, more porous texture than baking powder. It smells alarming during baking but the smell disappears completely when cooled. Vin Santo should be served in small glasses that are wide enough to dip without splashing — the cantucci go in whole and are removed before they fully dissolve.
Using butter — creates a shortbread-like crumb that will not survive dipping. Not baking long enough in the second bake — the cantucci must be fully dry inside; soft centres will become soggy the moment they touch wine. Slicing too thick — the centre takes too long to dry out. Blanching the almonds — traditional cantucci use whole, skin-on almonds.
Pellegrino Artusi, La Scienza in Cucina; Marcella Hazan, Marcella's Italian Kitchen