Method

• 1.
  Preheat the oven to 180°C.
• 2.
  For the cookies, place hazelnuts on a baking tray and roast for 5 minutes or until golden. Transfer to a large clean tea towel, enclose in towel and rub to remove some of the skins. Discard skins and coarsely chop nuts. Set aside to completely cool.
• 3.
  In a stand mixer fitted with the paddle attachment, beat butter and sugars for 4 minutes or until pale. Add vanilla and eggs, 1 at a time, beating well between each addition. Sift flour, cocoa, bicarb, baking powder and 1/2 tsp salt flakes in a bowl, then stir dry ingredients into butter mixture. Stir through chocolates and hazelnut. Divide dough into even pieces and shape into two 5cm-thick logs. Wrap each log in baking paper, then chill for 2 hours or until firm (logs can be stored, chilled, for up to 1 week, or frozen for up to 3 months).
• 4.
  Grease 2 large baking trays and line with baking paper.
• 5.
  Cut logs into 2cm-thick slices and place on prepared trays. Press out to 9cm diameter rounds, leaving a 3cm gap between each cookie. Scatter with a pinch of salt flakes and bake for 15 minutes or until a cookie has spread and top is set. Stand on trays for 5 minutes, then transfer cookies to a wire rack to completely cool.
• 6.
  To make the semifreddo, in a stand mixer fitted with the whisk attachment, whisk egg yolks until pale. Transfer to a bowl. Using a hand whisk, whisk honey and yoghurt together in a bowl until well combined. In the cleaned stand mixer, whisk cream and vanilla seeds to soft peaks, then transfer to a bowl. In the cleaned stand mixer, whisk eggwhites to soft peaks and, with the motor running, gradually whisk in sugar until dissolved.
• 7.
  Add yoghurt mixture and cream mixture to whisked egg yolk and fold through until combined. Fold eggwhite mixture through egg yolk mixture. Break up 200g cookies and fold into semifreddo mixture. Pour into an 8-cup (2L) loaf pan and freeze for 4 hours or overnight until frozen. Sandwich scoops of semifreddo between 2 cookies and serve immediately.