What fills the profiteroles in a croquembouche?

The profiteroles in a croquembouche are filled with limoncello cream.

Profiteroles must be filled and eaten on the day they’re made – if stored the pastry goes soft very quickly. Once the profiteroles are cold, make a hole using a skewer or small kitchen knife in the bottom of each one and pipe in your crème patissière. The profiteroles must be filled and eaten on the day they’re made – if stored the pastry goes soft very quickly. Once the profiteroles are cold, make a hole using a skewer or small kitchen knife in the bottom of each one and pipe in your crème patissière. To make this specific crème patissière recipe: Put both pod and seeds into a heavy based saucepan with the milk and bring to the boil, to infuse the vanilla. Meanwhile place the egg yolks and the 125g of sugar in a bowl and mix together for a few seconds, then sift in the flour and mix again. Pour the just-boiling milk over the yolk mixture, whisking constantly to prevent curdling, then return the mixture to the saucepan. Cook over a medium heat, whisking constantly for about 5 minutes, until very thick. Pass through a fine sieve, discarding the vanilla, and place a sheet of clingfilm on the surface of the custard to prevent a skin forming. Leave to cool, then refrigerate. Whip the cream and the 2 tablespoons of sugar together until thick but not over-whipped and fold into the chilled custard.