Heat the milk with the vanilla beans. Bring to a boil. Remove from heat, cover, and let steep for 30 minutes.

In a bowl, whisk the egg yolks with the sugar until the mixture becomes pale. Add the flour and mix.

Remove the vanilla beans. Pour the hot milk over the egg mixture while whisking. Pour everything back into the saucepan. Cook over low heat until the cream thickens. Cover with plastic wrap directly on the surface.

In a separate bowl, whip the heavy cream until stiff peaks form. Fold it into the pastry cream. Refrigerate.

In a skillet, make a dry caramel with the sugar. Add the hazelnuts and almonds. Coat them in the caramel and transfer to a sheet of parchment paper. Let cool. Process in a food processor until smooth. Add this praline paste to the pastry cream. Transfer to a piping bag and fill your choux pastries.