Lemon Icebox Pie

Whisk eggs and 2/3 cup sugar in a heavy, medium, nonreactive saucepan until smooth. Whisk in lemon juice. Cook over low heat, whisking constantly, until slightly thickened, 7 to 10 minutes. (Do not let mixture come to a simmer.) Pour through a fine-mesh sieve into a bowl. Stir in lemon zest. Place plastic wrap directly on the surface of the filling and refrigerate until thoroughly chilled, about 2 hours.

Combine warm water, powdered egg whites and cream of tartar in a mixing bowl. Stir gently until egg whites are dissolved, about 2 minutes. Beat with an electric mixer on medium-high speed until soft peaks form. Gradually add remaining 1/3 cup sugar, beating until stiff and glossy.

Beat cream in a small chilled bowl with chilled beaters with an electric mixer on medium speed until soft peaks form. (Alternatively, use a chilled wire whisk.)

With a rubber spatula, gently fold chilled lemon mixture into beaten egg whites; fold in whipped cream. Pour filling into crust and smooth the top. Freeze, uncovered, until firm, about 1 hour. Cover and freeze for at least 6 hours more.

Soften pie in the refrigerator for 20 to 30 minutes before slicing. Garnish with mint leaves and lemon slices.