In a food processor, combine flour and powdered sugar, pulsing until evenly mixed. Add cold butter and pulse until crumbly; then mix in the egg yolk and cold water until the dough forms a ball. Wrap in plastic wrap and chill in the refrigerator for 30 minutes to ensure a flaky texture.

Preheat your oven to 350°F (175°C). On a floured surface, roll out the chilled dough about 1/4 inch thick. Carefully press the rolled dough into mini tart pans, ensuring even coverage on the bottom and sides. Bake for 10-12 minutes, or until golden brown, watching for that perfect color. Remove the tart shells and let them cool completely on a wire rack.

In a medium saucepan, whisk together fresh lemon juice, lemon zest, sugar, and eggs. Heat over medium while stirring continuously until the mixture thickens and coats the back of a spoon, about 8-10 minutes. Once thickened, remove from heat and whisk in cold butter until melted and smooth. Allow the lemon curd to cool slightly before pouring it into the cooled tart shells, then chill for one hour to set.

In a heatproof bowl, combine egg whites, sugar, and cream of tartar. Place the bowl over a pot of simmering water, whisking constantly until the mixture becomes warm and sugar dissolves, about 3 minutes. Once warmed, remove from heat and using an electric mixer, beat until stiff peaks form, approximately 5-7 minutes. Gently fold in vanilla extract and violet food coloring.

Using a piping bag fitted with your favorite tip, fill it with the lilac meringue. Generously pipe the meringue onto each Mini Lemon Tart, creating whimsical swirls and peaks.

Carefully use a kitchen torch to lightly toast the tips of the meringue until golden brown. Garnish the tarts with edible lilac petals or dried lavender for elegance.