The recipe for Creamy Potato Gratin calls for double cream. Is it possible to use soured cream instead?
Nigella's Creamy Potato Gratin (from Nigella Bites and on the Nigella website) recipe simmers sliced potatoes and garlic in a mixture of full fat (whole) milk and double cream and then transfers the mixture to a dish for baking. The richness comes from the fat content in the double cream, along with the reduction of the milk and cream as the potatoes simmer.
It can be difficult to cook with sour cream as it has a lower fat content than most creams and has a tendancy to curdle or split when heated. As it is mixed with milk in this recipe it should be more stable so we believe it is possible to use sour cream, though we would prefer to use full fat creme fraiche as an alternative. If you are not in the UK then you can use a whipping cream or in the US heavy cream as an alternative to double cream.