Line Tin: Line a 20cm x 20cm (8 x 8-inch) square baking tin with baking paper. Set aside.
Prepare Biscuits: In a high-speed food processor, pulse the biscuits just a few times until you have a mixture of fine crumbs and plenty of larger biscuit pieces, with about one-third of the biscuits still remaining chunky. Do not over-process them, as the larger biscuit pieces are what give hedgehog slice its signature texture. Alternatively, place the biscuits in a zip-lock bag and gently crush them with a rolling pin, leaving plenty of visible chunks.
Combine Dry Ingredients: Add the crushed biscuits to a large mixing bowl. Add the desiccated coconut, lemon zest and salt. Mix until well combined. Set aside.
Melt: In a saucepan, combine the sweetened condensed milk and cubed butter. Heat over low-medium heat, stirring until the butter has completely melted and the mixture is smooth. Remove from the heat.
Combine: Pour the melted condensed milk and butter mixture into the biscuit mixture. Use a wooden spoon or spatula to mix until well combined.
Transfer Mixture: Spoon the mixture into the lined tin and press down firmly into an even layer. Set aside.
Topping
Melt Chocolate: Melt the white chocolate and coconut oil in a double boiler over low heat or in the microwave until smooth.
Pour and Spread: Pour the melted chocolate over the base. Gently tilt the pan to spread the chocolate evenly across the surface.
Chill: Refrigerate for at least 4 hours, or preferably overnight, until firm.
Slice and Serve: Lift the slice out of the tin using the baking paper and place it on a chopping board. Let it sit at room temperature for about 15 minutes so the chocolate can soften slightly, helping to prevent it from cracking when cut. Run a sharp knife under hot water, wipe it dry, then cut into squares and enjoy!
Video
Notes
Storage: Store the hedgehog in an airtight container in the refrigerator for up to 1 week.Freeze: For longer storage, wrap the entire slab or individual slices in cling film, then place in a freezer-safe bag or container. It can be frozen for up to 3 months.Thaw: Thaw the slices in the refrigerator overnight. For quicker thawing, leave them at room temperature for a few hours until they are soft enough to eat.