Combine all-purpose flour and powdered sugar in a food processor. Add chilled unsalted butter, pulsing until resembling coarse crumbs. Incorporate egg yolk and ice water until just combined. Chill for 30 minutes.

Preheat oven to 350°F (175°C). Roll out the dough, press into mini tart pans, and bake for 10-12 minutes until golden. Allow to cool completely.

Whisk together lemon juice, lemon zest, granulated sugar, and eggs in a medium saucepan. Cook over medium heat, stirring constantly for 8-10 minutes until thickened. Stir in cold butter until smooth.

Pour lemon curd into cooled tart shells and chill in refrigerator for at least 1 hour.

Whisk egg whites, granulated sugar, and cream of tartar in a heatproof bowl over simmering water until warm and sugar dissolves, about 3-5 minutes.

Remove from heat and whip with a stand mixer or electric beaters until stiff peaks form, about 5-7 minutes. Fold in vanilla extract and violet food coloring.

Pipe meringue onto each mini tart using a star tip, then lightly toast tips with a kitchen torch. Garnish with edible lilac petals or dried lavender.