I followed the White Chocolate Cheesecake recipe and it was good, but when I added the lemon juice the batter curdled. What could be done to avoid this?
Nigella's White Chocolate Cheesecake is a no-bake cheesecake that has a light, almost moussey texture. The filling is made with a combination of white chocolate and whipped cream. Lemon juice is added to help the mixture from becoming too cloyingly sweet. We suspect that it was not the lemon juice itself that cause the mixture to curdle, but more likely that the mixture had been stirred or mixed a little too much and had started to separate.
Cream will start to separate when it is whipped or beaten too much and when you fold the already whipped cream into the chocolate mixture it continues the beating action. We would suggest whipping the cream just until it is thickened and starting to hold its shape, it does not need to be beaten to soft peaks. If you are nervous about mixing the filling thoroughly then you can mix the vanilla and lemon juice into the chocolate mixture before the cream, then fold in a couple of spoonfuls of the whipped cream to soften the mixture, before folding in the remaining cream.