Burn the barbs off the prickly pears by holding them with tongs over a flame. Peel the fruit, then
puree it in a food processor or blender. Strain and mix with cranberry juice, lemon juice and salt.
Mix pear mixture with about one-third of its volume of the water-sugar syrup, stirring well. Put in a
4-quart ice cream churn container and add one uncooked egg, in its shell, which has been washed
carefully and dried with paper towels. A patch of the egg's surface, between the size of a dime and a
quarter, should show. If it does not, gradually add more syrup until the small white eye of the shell
appears. Remove egg and discard. Churn sorbet mixture until it turns opaque and to superfine ice. It
will be ready to serve at just about the same time as the machine stops. Sorbet can be kept in the
freezer after churning for a few hours, but its silky texture changes the longer it is frozen. Scoop
and garnish with a sprig of mint.