I adapted one of my aunt’s ‘proper’ recipes for this. You’ll need something like
Some Madeira cake or fairy cakes from the reduced to clear pile (or make your own)
Some bananas or other soft or tinned fruit
Cocoa (or powdered coffee if you’re into that)
Fine sugar or icing sugar
You can make one big molehill take or several small ones. For either size cut the cake(s) apart into slices and arrange them to the desired base sizes. Leave some behind for the topping.
Slice bananas and/or other fruit. Whip cream very stiff and arrange into a vaguely even ‘hill’ on top of the fruit.
Crumble the remaining cake over the cream hills and sprinkle everything with a chocolate-sugar mixture until they resemble mole hills. In the unlikely event that you have some marzipan in the fridge and some food colouring, you could model some tiny moles that climb out of the mounts… 😉