Fine Buttercream

Bring whole milk with the seeds from half a vanilla pod to the boil in a small pot and simmer gently for 5 minutes.

Whisk the egg yolks, sugar and cornstarch in a bowl until smooth.

Gradually pour the hot vanilla milk into the egg-yolk mixture while stirring.

Stir the custard until smooth and let it cool completely.

Beat the softened butter with powdered sugar until pale and fluffy.

Fold the cooled vanilla custard into the butter spoonful by spoonful until a smooth buttercream forms.

Use the buttercream immediately as desired or chill briefly until spreadable.