Grease the tin and heat pan. Begin by greasing the cake tin with a generous layer of butter and then line the bottom with baking parchment. Next, preheat a medium-sized, nonstick frying pan
Toast the nuts. Add the almonds and pine nuts to the pan and dry-fry them over medium heat for approximately 3 minutes or until they turn a lovely golden color. Make sure to turn them frequently for even browning. Transfer these toasted nuts into a small bowl and set them aside.
Melt butter & chocolate. In a large heatproof bowl, positioned over a pan of gently simmering water (ensuring the base of the bowl doesn't touch the water), combine the butter, syrup, and half of the chocolate. Once the chocolate has melted, remove the bowl from the pan.
Finish the tiffin base. Stir in the cocoa, followed by the apricots and the dry-roasted almonds and pine nuts. Crumble the amaretti biscuits into the mixture coarsely and stir everything gently to achieve a uniform blend.
Tip mixture into tin. Transfer this combined mixture into the prepared tin and use a palette knife to press it down, leveling the surface.
Refrigerate. Cover the tin and place it in the refrigerator to set for at least 3 hours or, ideally, overnight. When ready, remove the tin from the fridge.
Prepare the chocolate topping. Now, put the remaining half of the chocolate in a heatproof bowl over simmering water, melt it, and then remove the bowl from the pan. Pour the melted chocolate evenly over the biscuit base, spreading it thinly across the surface. Allow it to set for at least 30 minutes.
Cut the chocolate bars. Use a sharp knife to cut the mixture into 18 bars, and carefully remove them from the tin. For an elegant finishing touch, decorate each bar with edible gold leaf.