In a mixing bowl, combine flour, powdered sugar, and salt. Cut in chilled butter until the mixture resembles coarse crumbs. Roll out the dough, cut into circles, and place into tart pans. Chill for 30 minutes.

Preheat your oven to 350°F (175°C). Bake chilled shells for 15-20 minutes until golden brown. Keep an eye to avoid overbaking.

In a saucepan, whisk lemon juice, granulated sugar, eggs, lemon zest, and vanilla extract over medium heat. Cook until thickened, about 8-10 minutes. Pour into cooled tart shells.

Beat egg whites until soft peaks form. Gradually add sugar, continue beating until stiff peaks form. Fold in lilac food coloring if desired.

Pipe meringue onto tarts, covering lemon curd completely.

Toast meringue using a kitchen torch until golden brown, or under a low broiler for about 1 minute.

Optionally garnish with fresh mint leaves and serve chilled.