Crust

1. Place the Oreos in a food processor and blitz until a smooth crumb
2. Add the melted butter and pulse until combined
3. Grease 6 tartlet moulds and press the oreo crumbs into the base and sides
4. Optional: Bake at 160C/320F for 10 mins, then cool before adding the filling for a crisper base

Filling

1. Finely chop the chocolate and place it in a large heatproof bowl
2. Heat half the cream (1/2 cup) in the microwave or a small saucepan until just steaming
3. Pour the hot cream over the chocolate and cover with a plate, let it sit for 5-10 mins until the chocolate is melted
4. Add the salt and butter, and stir until smooth
5. Add the remaining cream and rum and stir until well combined
6. Divide the chocolate mixture among the prepared tartlet shells
7. Place the assembled tarts in the fridge to chill overnight, or a minimum of 4 hours before consuming
8. Top with a dollop of cream, chocolate shavings or a dusting of cocoa powder to serve