Can I Make the Grasshopper Pie With Condensed Milk Instead Of Marshmallows?

Our answer

Nigella's Grasshopper Pie (from KITCHEN) has a chocolate cookie crust and a filling that is inspired by the Grasshopper cocktail - flavoured with crème de menthe and white crème de cacao. The Chocolate Key Lime Pie (from the same book) is slightly more traditional with a creamy, citrussy filling.

Unfortunately we don't think that the marshmallows can be swapped for sweetened condensed milk. The filling for Grasshopper Pie is slightly moussey and melts in the mouth. The gelatine in the marshmallows sets as the mixture cools, firming up the filling slightly and giving it the light texture. For the Key Lime Pie the acidic lime juice in the filling not only acts to cut through the sweetness of the condensed milk but also helps to slightly thicken the mixture as it reacts with (stabilises) the whipped cream. Without the acid the filling would be slightly runnier. We are not sure what the exact problem is with combining the marshmallow mixture and whipped cream for the Grasshopper Pie, but if it starts to look curdled it could be that the marshmallow mixture was too warm or the mixture has become over whisked. Stir the marshmallow mixture occasionally until it has cooled to room temperature before using it. If you are using British double cream then whisk the cream until it only just reaches soft peaks before adding the marshmallow as it will be whisked more as you incorporate the marshmallow. If using heavy or whipping cream then whisk to soft peaks as it has a lower fat content than double cream and so needs slightly more whipping. Also, if you are using food colouring then it may help to add a couple of drops to the cream before you start whisking it to reduce the risk of the cream being over whisked at the end.