Custard for a layered cake is cooled fast and kept cold

For New Year I usually make a tall layered cake: thin crisp layers sandwiched with a rich custard cream, left overnight to soften, then cut into neat slices. For me, it is the cake that means celebration. It is also a cake that needs respect, because the filling is made of milk, eggs and butter, and cream fillings are exactly where bacteria like to grow if they are left warm.

So the most important part of the recipe, for me, is not the pastry. It is how I cook and cool the custard.

For a cake for ten to twelve people I make the custard with one litre of whole milk, four eggs, 200 g of sugar, 60 g of plain flour or cornflour, a little vanilla, and 200 g of soft butter beaten in at the end.

I whisk the eggs, sugar and flour together in a bowl until smooth. I heat the milk in a heavy pan until it is just steaming, then pour some of it onto the egg mixture, whisking all the time, and pour everything back into the pan. Then I stir it over a medium heat, without stopping, scraping the bottom and corners, until it boils and thickens. It needs to bubble gently for a minute or two, still stirring. This cooks the flour, so it does not taste raw, and it cooks the eggs properly.

Then cooling. A pan of thick custard stays warm for a very long time, and warm custard is the danger. So I pour it straight into a wide, shallow dish, press a sheet of baking paper onto the surface so no skin forms, and stand the dish in a sink of cold water with a few ice cubes. I stir it now and then. Once it is cool, it goes into the fridge. I aim to have it in the fridge within an hour and a half, never longer than two hours.

When it is completely cold, I beat the soft butter until pale and creamy and add the custard to it a spoonful at a time. This turns it into a light, smooth cream. If the custard is still warm, the butter melts and the cream splits, which is another reason to cool it properly.

I assemble the cake on its board, spreading the cream between the layers and over the top and sides, then I crumble the trimmings over it. The finished cake goes straight into the fridge, covered, for at least eight hours or overnight. It needs that time to soften, and it needs to be cold.

It stays in the fridge until just before serving. A cream cake is not something to leave on the table all evening while people talk; I take it out, cut it, serve it and put the rest back, within two hours. In the fridge, it keeps for up to three days.

The cake contains milk, eggs, wheat and butter, and some versions have nuts, so I mention it to guests.

My Napoleon cake is in the Recipes section of this site, with the layers explained step by step; this note is only about the custard, because that is where the care is needed.

Custard cream for a layered cake. For a cake for 10–12. About 30 minutes plus cooling. You need 1 litre whole milk, 4 eggs, 200 g sugar, 60 g flour or cornflour, vanilla and 200 g soft butter. Whisk the eggs, sugar and flour, add the hot milk, return to the pan and stir until it boils and thickens, then cook a minute more. Cool fast in a shallow dish over iced water and chill within two hours. Beat into the soft butter when completely cold.

What cake means celebration in your family?