Prepare Pan: Line an 8-inch x 8-inch (20cm x 20cm) baking pan with parchment paper and set aside.
Crush Biscuits: In a food processor, crush biscuits into crumbs, leaving some larger chunks for texture. Transfer to a large mixing bowl.
Mix Dry Ingredients: Add Milo and desiccated coconut to the biscuits. Mix until well combined.
Add Condensed Milk: Pour in condensed milk and thoroughly mix with a wooden spoon until all dry ingredients are well coated. Using your hands may be helpful for better mixing.
Press Mixture: Spoon the mixture into the lined pan and press into an even layer.
Chill: Place in the refrigerator for 30 minutes until just set.
Topping
Melt Chocolate: Prepare a double boiler with a heat-proof mixing bowl over simmering water. Add chocolate and gently melt over low-medium heat, stirring occasionally. Once completely melted, turn off the heat. Allow residual heat to continue melting any remaining chunks.
Add Topping: Remove the slice from the refrigerator. Carefully pour the melted chocolate over the base, tilting the pan or using a spatula to spread the chocolate evenly.
Chill Again: Transfer to the refrigerator for 2-3 hours until completely hardened, or ideally overnight to allow the base to firm up.
Soften for Slicing: Before slicing, remove from the pan and let sit at room temperature for 10-15 minutes. This softens the chocolate slightly, making it easier to cut through and preventing it from cracking.
Cut and Enjoy: Slice into rectangles or squares. Enjoy!
Notes
Storage: Store the slice 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.