This is the most deliciously fresh sorbet Marcella Hazan knows. What makes it so is the felicity with which the ingredients act upon each other. The Granny Smith apples and the grappa both have bite, but the grappa isn't all bite. It is packed with the aromatic esters of the pomace, the grape skins left over after making wine, from which it is distilled. The honey is all suavity with its characteristically musky aftertaste. The Muscat brings its own soft touch and the scent of peaches and apricots. These qualities don't stand apart, but coalesce to produce this sorbet's unique, zephyr-like refreshment.
If you have all the choices in the world, use the low-alcohol Moscato naturale d'Asti, a shyly sweet Muscat from Piedmont. Only slightly less desirable, but far more available, is Asti Spumante, which you must beat lightly with a fork to drive away some of the bubbles.
In a small saucepan, combine the sugar, honey and 1 cup of water and bring to a boil over low heat. cook until the syrup has reduced by half, about 10 minutes. Let cool.
Meanwhile, peel and core the apples and cut them into walnut-size pieces.
In a food processor, combine the apples, sugar syrup, Muscat, lemon juice and grappa and puree until creamy. Transfer the mixture to an ice cream maker and freeze until firm. Serve at once or transfer the sorbet to chilled containers and store in the freezer.