Pulse together flour and powdered sugar in a food processor until combined. Add cold butter and blend until the mixture resembles coarse crumbs. Mix in the egg yolk and water until a dough forms. Chill the dough for 30 minutes.

Preheat your oven to 350°F (175°C). Roll out the dough and press it into mini tart pans. Prick the bases, line with parchment paper, and fill with weights. Bake for 10-12 minutes until lightly golden. Cool the shells.

In a medium saucepan, whisk together lemon juice, zest, sugar, and eggs. Heat over medium while stirring until thickened, about 8-10 minutes. Remove from heat and whisk in unsalted butter. Cool slightly and pour into tart shells.

Cover with plastic wrap and refrigerate for at least 1 hour to allow the lemon curd to set.

Set a heatproof bowl over simmering water. Combine egg whites, sugar, and cream of tartar. Whisk until warm and sugar dissolves, about 4-5 minutes. Beat with mixer until stiff peaks form.

Fold in vanilla extract and violet food coloring until evenly mixed.

Pipe the lilac meringue onto each tart, ensuring coverage of the lemon curd.

Toast the meringue tips with a kitchen torch until golden brown, moving the torch to prevent burning.

Garnish with edible lilac petals or dried lavender. Serve chilled.