Creme Patissiere For Gooey Chocolate Stack

Our answer

Nigella's Gooey Chocolate Stack (from HOW TO BE A DOMESTIC GODDESS) is a dessert made of layers of chocolate meringue and chocolate flavoured creme patissiere. The creme patisserie should have a thick but still spreadable consistency. The creme patissiere is thickened with a combination of egg yolks and flour. The flour not only thickens the mixture but also helps to stabilise the egg yolks so that they can be brought up to boiling point.

From the descriptions we suspect that the first batch of creme patissiere was undercooked but the second batch was overcooked. The first batch had a floury taste, which is a good sign that it had not been cooked quite enough and so will be too thin. For the second batch the mixture being boiled for a minute can cause the mixture to overcook. In this case the mixture can turn slightly grainy and may become runny again. We would suggest using a medium-low heat, stirring or whisking constantly, and cooking the mixture until it just comes to boiling point - but do not let it actually boil. If you are unsure you can take the mixture off the heat and carefully taste a little. If you can taste the flour, return to the heat and cook for a little longer before checking again. Once the mixture has thickened enough, take it off the heat and whisk for a minute to help the mixture cool slightly. We would also avoid using a cast iron pan for this as it can hold the heat a little too efficiently and will remain quite hot even when taken off the heat. Graininess can also be caused by adding hot milk and cream too quickly to the egg, sugar and flour base. We suggest adding a little of the hot milk and cream first (about 100ml/generous 1/3 cup) and whisking well until smooth, then whisking in the remainder in a thin stream. You can also strain the egg and milk mixture before returning it to the saucepan to remove any fine lumps. Finally, make sure that the cooked creme patissiere has cooled slightly before adding the chocolate as if it is too hot this can also cause the chocolate to seize, giving a grainy texture. You should also assemble the stack just before serving as the meringue will absorb moisture from the filling and become soft quite quickly.