Combine all-purpose flour and powdered sugar in a food processor. Add cold butter and pulse until resembling coarse crumbs. Mix in egg yolk and ice water until a dough forms. Chill for 30 minutes.

Roll out the chilled dough and cut circles to press into mini tart pans. Prick bases with a fork, blind bake with parchment paper and pie weights for 10-12 minutes. Cool completely.

In a saucepan, whisk together lemon juice, zest, granulated sugar, and eggs over medium heat for 8-10 minutes until thick. Remove from heat, add unsalted butter and stir until smooth. Cool slightly before pouring into tart shells.

Chill filled tarts in the refrigerator for at least one hour.

In a heatproof bowl, combine egg whites, granulated sugar, and cream of tartar. Whisk over simmering water until warm, then beat until stiff peaks form. Add vanilla and food coloring.

Pipe meringue onto the cooled lemon curd in beautiful swirls.

Toast the meringue with a kitchen torch, and garnish with edible lilac petals or dried lavender.