Line an 8-inch square pan with parchment paper.
Melt chopped dark chocolate in a heatproof bowl set over a pot of barely simmering water.
Melt until almost all the chunks are gone, take off heat and continue stirring until smooth.
Spread into a parchment lined square pan, allow to set for 2 minutes (not all the way) then add your toppings.
Allow to chill on table for 10 minutes then place in freezer for 10 minutes to fully set.
Slice with sharp chef’s knife or break with hands to create shards.