Add Oreo biscuits in a food processor bowl and blend until crumbs form. Pour in melted butter and process until evenly moistened.
Press this mixture evenly into the bottom and sides using your fingers in a tart tin. Leave the center hollow to fill in chocolate filling.
Refrigerate this tart shell to harden. Start making ganache by adding the dark chocolate and heavy cream to a sauce pan.
On a low flame, heat this until chocolate completely melts and the mixture turns glossy.
Now remove tart shell from fridge and pour over this ganache in the center. Refrigerate for 30 minutes or until set.
Pit and slice the cherries into half or you can leave whole. After ganache has set decorate with cherries and serve chilled.