Dissolve the sugar in the water and bring to a boil in a saucepan over medium heat. Pare pears, but leave the stems; carefully drop them into the boiling syrup. Boil the pears until they are tender when prodded with a toothpick.
Remove pears from the saucepan and spangle each one abundantly with almond slivers.
Reduce the syrup to half its original volume by letting it boil uncovered. Pour the thickened syrup over the pears, which may now be refrigerated until shortly before serving time.
Half an hour before serving, arrange the pears on a fireproof platter, and make sure they are well covered with syrup. Reheat them in a 200°C / 400°F oven for about 10 minutes.
Warm both liqueurs together over low heat. Bring the platter of hot pears to the table, pour the liqueurs over them, and set alight with a match. The fragrance is delightful, the flavours subtle and sweet. The pears may be served with whipped cream or shortbread.