Lemon-Cream Meringue Tarts

Preheat oven to 225F.
Line large baking sheet with parchment paper.
Using electric mixer, beat egg whites and cream of tartar in large bowl until soft peaks form.
Gradually add sugar, 1 tablespoon at a time, and beat until stiff and glossy, about 8 minutes.
Using generous 1/3 cup meringue for each, scoop 8 dollops of meringue onto prepared baking sheet, spacing apart.
Using back of spoon, make 2 1/2-inch-wide indentation in center of each meringue, spreading meringues to form 3 1/2-inch-diameter nests.
Bake meringues until crisp, about 1 1/2 hours.
Cool.
(Can be made 1 day ahead.
Store airtight at room temperature.)
Bring 1/2 cup cream to simmer in heavy medium saucepan over medium heat.
Add 8 mint sprigs; remove from heat.
Cover; let steep 30 minutes.
Strain mixture into bowl; discard mint.
Combine egg yolks, sugar, lemon juice, and lemon peel in heavy medium saucepan.
Whisk constantly over medium-low heat until mixture thickens and instant-read thermometer inserted into mixture registers 160F, about 5 minutes.
Transfer custard to glass bowl; whisk in mint-infused cream.
Refrigerate until cold, at least 1 hour.
Using electric mixer, beat remaining 1/2 cup cream in medium bowl until peaks form.
Fold into lemon mixture.
(Filling can be made 6 hours ahead.
Cover and refrigerate.)
Spoon filling into meringue shells.
Garnish with additional mint sprigs.