Creating the Mini Lemon Tart with Lilac Meringue can be a straightforward process following these steps:

For the Tart Shell:

1. Prepare the Tart Shell: In a mixing bowl, combine flour and powdered sugar. Add chilled butter and mix until crumbly.
2. Add Egg Yolk: Stir in the egg yolk and add ice water gradually until the mixture forms a dough.
3. Chill the Dough: Form the dough into a disk, wrap it in plastic, and refrigerate for 30 minutes.
4. Roll Out: Preheat the oven to 350°F (175°C). Roll out the dough on a lightly floured surface to fit mini tart pans.
5. Line Tart Pans: Press the dough into the pans. Prick the bottom with a fork to prevent bubbling.
6. Bake the Shells: Bake for 12-15 minutes or until lightly golden. Let cool.

For the Lemon Curd:

7. Mix the Ingredients: In a saucepan, whisk together eggs, sugar, lemon juice, and zest.
8. Cook Over Medium Heat: Add the butter and cook while stirring constantly until thickened (about 10 minutes).
9. Strain the Curd: Remove from heat and strain the mixture to remove lumps.
10. Fill Tart Shells: Spoon the lemon curd into the cooled tart shells and refrigerate for at least 1 hour.

For the Lilac Meringue:

11. Whip Egg Whites: In a clean mixing bowl, beat the egg whites and cream of tartar until soft peaks form.
12. Add Sugar Gradually: Slowly add sugar, continuing to beat until stiff peaks form. Mix in the vanilla and lilac coloring if desired.
13. Pipe the Meringue: Transfer the meringue to a piping bag. Pipe onto the cooled lemon curd-filled tarts.
14. Toast the Meringue: Use a kitchen torch or broiler to lightly toast the meringue for a golden finish.