In a medium saucepan, combine the cream, 1 cup of the milk and 1 cup of the sugar.
Warm over moderate heat, stirring, just until steaming.
In a large bowl, whisk the eggs and the remaining 1 cup of milk until smooth.
Slowly pour in the hot cream, whisking constantly, until combined.
Return the mixture to the saucepan and cook over moderate heat, stirring constantly, until it coats the back of a wooden spoon, about 8 minutes.
Strain the custard into a bowl and refrigerate until chilled.
In a bowl, combine the peaches with the balsamic vinegar, the pepper and 1 tablespoon of sugar and let stand for 10 minutes; add more sugar if necessary.
Divide the peaches among 8 bowls and top with scoops of the gelato.