Wash 1 lemon, cut into slices. Put wine, juice and liqueur in a large pot. Cut open the vanilla pod. Add lemon slices and sugar, bring to the boil while stirring. Simmer on low heat until the sugar is dissolved
Squeeze the remaining lemon. Peel pears and sprinkle with lemon juice. Cook in the stock at low heat for about 30 minutes. Turn from time to time so that they turn red evenly. Leave to cool in the syrup