Tegole valdostane

Step 1: Heat the oven to 350°F (325°F fan) and line 2 baking trays with baking paper.

Step 2: Grind 2 ⅛ oz blanched almonds and 2 ⅛ oz toasted skinned hazelnuts with 2 tbsp of 4 oz caster sugar in a food processor to a fine, sandy meal, stopping before it turns oily.

Step 3: Whisk 3 egg whites with the rest of the sugar and 1 pinch salt for about 1 minute, just until foamy and loose; you are not making a meringue.

Step 4: Fold in the nut meal, ⅔ oz potato starch and ½ tsp vanilla extract, then the cooled 1 ¾ oz butter, until you have a smooth, runny batter.

Step 5: Drop level teaspoons on a tray, 6 per tray and well apart, and spread each with the back of a wet spoon into a 7 cm circle. Common mistake: leaving them thick; the centres stay soft, so spread until you can almost see the paper.

Step 6: Bake for 8–10 minutes, until the edges are golden brown and the middles pale gold.

Step 7: Working fast, lift each biscuit with a palette knife and drape it over a rolling pin for 1 minute until set in a curve. If they harden on the tray, warm them in the oven for 30 seconds.

Step 8: Repeat with the rest of the batter, then store the cooled tegole in an airtight tin for up to a week.