Melt the butter in the microwave or on the stovetop.
Crush Oreo cookies into fine crumbs using a food processor.
Mix crumbs with melted butter until the texture resembles wet sand.
Press the mixture firmly into a tart pan, including the sides.
Freeze the crust for 10 minutes to set.
Chop the chocolate into small pieces and place in a bowl.
Heat the cream until hot but not boiling.
Pour hot cream over the chocolate and let sit for 3–4 minutes.
Stir until smooth to create a glossy ganache.
Pour ganache into the chilled crust and spread evenly.
Arrange raspberries on top of the ganache.
Refrigerate for at least 2 hours until set.
Dust with powdered sugar before serving if desired.
This Chocolate Raspberry Tart is best served chilled for a smooth and rich texture.