Wash the lemon hot, dry and finely grate the peel. Briefly mix butter, sugar and 1 pinch of salt with the whisk of the hand mixer. Stir in lemon zest and eggs. Mix 400 g flour and baking powder and sieve over it.
Pour in Vin Santo and knead everything with the dough hooks of the hand mixer. Knead the almonds well.
Preheat oven (electric cooker: 175°C/circulating air: 150°C/gas: level 2). Divide the dough into thirds and form one roll each (approx. 4 cm Ø). Place all on a baking tray lined with baking paper. Bake in a hot oven for about 20 minutes.
Remove and carefully cut the dough rolls into slices of approx. 1.5 cm thick. Place the cantuccini with the cut surface on two trays lined with baking paper. Bake again at the same temperature for about 8 minutes.
Let it cool down.
Cantuccini taste good with espresso or Vin Santo. In airtight containers they last about 2 weeks.