To make the base, the biscuits are first ground into fine crumbs, then mixed with cocoa powder and powdered vanilla. In a small saucepan, butter, milk, and sugar are gently heated until the sugar fully dissolves. This warm mixture is poured over the biscuit crumbs, followed by the rum aroma, and everything is mixed until fully combined.
The mixture is then pressed evenly into a baking-paper-lined pan (about half a standard baking tray). Itβs important to smooth the surface well so the slices look neat later. The base is left in a cool place for 1β2 hours to firm up.
For the topping, the dark chocolate is melted gently over steam, then mixed with a bit of oil to create a smooth, shiny glaze. This is spread evenly over the chilled base. Once the chocolate has fully set, the dessert is ready to slice.
Clean, sharp cuts will give you perfect, bakery-style pieces.