Preparation For mousse: Whisk first 3 ingredients in medium metal bowl. Set bowl over saucepan of simmering water (do not allow bottom of bowl to touch water); whisk constantly until candy thermometer registers 170°F, about 3 minutes. Remove bowl from over water. Add ginger and vanilla. Transfer mixture to processor and puree until fluffy, about 5 minutes. Pour puree into large bowl. Refrigerate until cool, about 20 minutes. Beat cream in another large bowl until stiff peaks form. Fold cream into egg mixture. Cover and freeze overnight. For sauce: Combine first 5 ingredients in heavy medium saucepan. Stir over medium heat until sugar dissolves and butter melts. Increase heat to high and boil until sauce thinly coats back of spoon, stirring occasionally, about 4 minutes. Cool slightly. (Mousse and sauce can be made 1 week ahead. Keep mousse frozen. Cover and refrigerate sauce. Before serving, stir sauce over low heat just until warm.) Spoon frozen mousse into 8 margarita glasses. Drizzle some warm sauce over each. Top with peaches and almonds.
Preparation For mousse: Whisk first 3 ingredients in medium metal bowl. Set bowl over saucepan of simmering water (do not allow bottom of bowl to touch water); whisk constantly until candy thermometer registers 170°F, about 3 minutes. Remove bowl from over water. Add ginger and vanilla. Transfer mixture to processor and puree until fluffy, about 5 minutes. Pour puree into large bowl. Refrigerate until cool, about 20 minutes. Beat cream in another large bowl until stiff peaks form. Fold cream into egg mixture. Cover and freeze overnight. For sauce: Combine first 5 ingredients in heavy medium saucepan. Stir over medium heat until sugar dissolves and butter melts. Increase heat to high and boil until sauce thinly coats back of spoon, stirring occasionally, about 4 minutes. Cool slightly. (Mousse and sauce can be made 1 week ahead. Keep mousse frozen. Cover and refrigerate sauce. Before serving, stir sauce over low heat just until warm.) Spoon frozen mousse into 8 margarita glasses. Drizzle some warm sauce over each. Top with peaches and almonds.