Are we supposed to use the full Oreo cookie (with creme filling) or just chocolate cookie wafers for the base of the Salted Chocolate Tart?
Nigella's Salted Chocolate Tart (from SIMPLY NIGELLA) has a base made from butter, dark chocolate and chocolate sandwich cookies (such as Oreos or Bourbon biscuits). You do need to use the creme filling from the cookies as this helps to bind the mixture together slightly and when the tart base is chilled it becomes firm.
It is easiest to make the base in a food processor and if you do this then we suggest that you snap the cookies into pieces first, so that they break down into crumbs more easily. If you use chocolate wafer cookies the you would need to use a larger amount of butter to help the mixture to bind together. The mixture should feel like very slightly damp sand once it has been processed.