Using tea towel, rub off as much pistachio skins as possible; chop nuts coarsely. In small heatproof bowl set over saucepan of hot, not boiling, water, melt chocolate. Stir in cherries, cranberries, apricots and nuts.

Place heart-shaped cookie cutters on parchment paper–lined metal tray. Spoon mixture into cutters until at least 1/3 inch/8 mm thick. Let cool in refrigerator until set. Remove from cutters (warm outside of cutters with hands and push out chocolates). Repeat with remaining chocolate mixture.