This intensely flavored sauce is a real treat served on ice cream, puddings, or poached fruit.
Heat the sugar and water in a small saucepan over medium heat, stirring from time to time, until the sugar dissolves completely, about 5 minutes.
Put the raspberries and the sugar syrup in a blender and puree.
Strain through a fine mesh sieve to remove the seeds and stir in the kirsch or framboise, if using.
The sauce keeps well, tightly covered, in the refrigerator for 4-5 days and freezes perfectly for several months.
