A plombiere is an ice cream mixture containing almonds or chestnuts. It may be frozen in a decorative mould but is more often scooped into balls and piled up to form a pyramid. It is often served with a sauce poured over the top.
2. Make an apricot marmalade by boiling the apricot jam in a small saucepan with a few drops of lemon juice until thick.
3. Keep a little aside for decoration and sieve the rest into a bowl.
4. Combine the egg yolks and caster sugar in a deep bowl and beat together until very thick.
5. Put the single cream in a saucepan and bring slowly to the boil.
6. Pour the cream over the yolks and sugar, stirring well. Return the mixture to the clean pan. Cook, stirring constantly, until the custard thickens. Do not allow it to boil.
7. Pour the thickened custard into a large bowl and stir in the sieved apricot marmalade, the vanilla essence and the ground almonds. Cover closely with dampened greaseproof paper and cool.
8. In a bowl, whip the double cream to the same consistency as the custard. Fold it into the custard, with the crushed macaroons.
9. Spoon the mixture into a suitable container for freezing (a bowl that is deep enough to allow the ice cream to be scooped is ideal). Freeze the mixture until firm.
10. To serve, scoop into balls, arranging these as a pyramid on a chilled plate. Drizzle the reserved apricot marmalade over the top and decorate with the ratafias.