1-First Step: Prepare the pan and ingredients Line a slice pan measuring 18×28 cm, 20×20 cm, or 8×8 inch with parchment paper, leaving an overhang on the sides. The overhang makes it much easier to lift the slice out later. Then gather all ingredients so everything is ready before you start melting.

2-Second Step: Break the biscuits and mix the dry ingredients Break the 250 grams digestive biscuits by hand into a mix of pieces and crumbs. Do not crush them too finely, since a few larger bits give the slice more crunch. Place the biscuits in a large bowl, then add the chopped walnuts and desiccated coconut. Stir gently so the dry ingredients are evenly combined.

3-Third Step: Melt the chocolate base Set a saucepan over low heat and add the butter, cocoa powder, sweetened condensed milk, and dark chocolate. Stir slowly and keep the heat low so the mixture melts without scorching. Once everything is smooth and glossy, remove it from the heat.

4-Fourth Step: Combine the wet and dry mixtures Pour the melted chocolate mixture over the biscuit, walnut, and coconut mixture. Stir well until every piece is coated. Work quickly but carefully, since the mixture will start thickening as it cools.

5-Fifth Step: Press into the pan and chill Spoon the mixture into the prepared pan and press it down firmly with the back of a spoon or spatula. A compact base helps the slice hold together when cut. Place the pan in the fridge for 30 minutes so the base can firm up before the topping goes on.

6-Sixth Step: Melt the milk chocolate topping Put the milk chocolate in a microwave-safe bowl and heat it in 30-second intervals on medium power. Stir between bursts so it melts evenly. When the chocolate is just melted, stir in the 2 teaspoons vegetable oil until smooth and shiny.

7-Seventh Step: Spread the topping and chill again Pour the melted milk chocolate over the chilled base and spread it evenly to the edges. Return the pan to the fridge for 1 to 2 hours, or until the topping is set. If you want cleaner slices, score the top with a knife when the chocolate is about 75 percent hardened.

8-Final Step: Slice and serve Once the slice is firm, lift it out using the parchment overhang. Cut it into 16 pieces with a sharp knife. For the cleanest cuts, avoid slicing while the chocolate is very cold, since cold chocolate can crack. Let it sit for a few minutes at room temperature if needed.