Cook
the pears with the sugar in a large pan for
10-15
minutes, or until very soft.
Let cool.
Melt the agar-agar with the lemon zest and
juice
and 2 tablespoons of the pear cooking liquid in a
small saucepan over low heat for 2 minutes, stirring
constantly.
Chop the pears and remaining cooking
liquid in a food processor until smooth. Add the gelling mixture and let stand until almost set.
Beat the egg whites in a large bowl with an
electric mixer at high speed until stiff.
Fold into the pureed pears
with half the hazelnuts.
Pour the mixture into four ramekins or custard cups.
Refrigerate for at least 2 hours.
Turn out onto serving dishes and
decorate with the remaining hazelnuts and lemon.