Melt the dark chocolate in the top part of a double boiler and set aside to cool. Line a 20 cm square cake tin with baking paper, allowing two sides to overhang for easy removal.
For the base layer, place the macadamias in a food processor and blend until smooth. Add the remaining ingredients and process until the mixture forms a ball. Press the mixture evenly into the lined cake tin and place in the freezer.
For the caramel layer, place the macadamias and dates in a food processor and blend until as smooth as possible. If necessary, use a blender to achieve a smooth consistency. Add the remaining ingredients and process until combined. Smooth the caramel over the base layer and return to the freezer for 15 minutes.
Remove the slice from the freezer and gently lift it from the tin. Place on a flat surface and pour the chocolate over to cover evenly. Before the chocolate has completely set, cut into squares.
Serve once the chocolate has set. Store in the fridge.