Tarte au Citron has always held a special place in my heart. Every time I slice through its delicate, buttery crust and reveal the vibrant, zesty filling inside, I'm transported straight to a quaint Parisian café on a sunny spring afternoon.
In a large bowl, combine the flour and powdered sugar. Add the cold, diced butter and gently rub it into the mixture using your fingertips until it resembles coarse breadcrumbs.Add the egg yolk and 2 tablespoons of cold water. Mix until the dough just comes together—add an extra tablespoon of water if necessary.Form the dough into a disc, wrap in cling film, and refrigerate for at least 30 minutes.
Roll out the dough on a lightly floured surface to fit a 23 cm tart pan.Press the dough into the pan, trim the edges, and prick the base with a fork.Chill for 15 minutes, then preheat your oven to 180°C (350°F) and bake the crust for 15 minutes or until lightly golden. Remove from the oven.
In a saucepan, whisk together the lemon juice, lemon zest, granulated sugar, and eggs.Cook over medium-low heat, stirring continuously until the mixture thickens to a custard-like consistency (about 10 minutes).Remove from heat and stir in the butter pieces until completely melted and smooth.
Pour the lemon filling into the warm pastry shell.Return to the oven and bake for an additional 5 minutes.Once cooled, garnish with candied lemon slices and fresh mint leaves.