Combine all-purpose flour, powdered sugar, and salt in a mixing bowl. Cut in the chilled butter until the mixture resembles coarse crumbs. Press the dough into a flat disc, roll it out on a floured surface, cut circles, and press into mini tart pans. Chill in the refrigerator for 30 minutes.

Preheat your oven to 350°F (175°C). Bake the tart shells for about 15-20 minutes until lightly golden. Cool completely.

In a saucepan, whisk together lemon juice, sugar, eggs, lemon zest, and vanilla. Cook over medium heat, stirring continuously for 8-10 minutes until thickened. Fill each tart shell with the lemon curd.

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

Pipe the lilac meringue onto the lemon curd in decorative swirls. Optionally, use a kitchen torch to lightly brown the meringue.

Garnish with fresh mint leaves and serve immediately for best flavor and texture.