Mix the Dry Ingredients: In a mixing bowl, whisk together the flour, sugar, and salt.

Incorporate the Butter: Add the cold, cubed butter and use a pastry cutter or your fingers to mix until the mixture resembles coarse crumbs.

Add the Egg Yolk: Stir in the egg yolk and 1 tablespoon of ice-cold water. Mix until the dough comes together, adding more water if needed.

Chill the Dough: Form the dough into a disc, wrap it in plastic wrap, and refrigerate for at least 30 minutes.

Roll Out and Pre-Bake: Roll out the chilled dough and press it into a 9-inch tart pan. Prick the bottom with a fork, line with parchment paper, and fill with pie weights or dried beans.

Blind Bake: Bake at 350°F (175°C) for 15 minutes. Remove the parchment and weights, then bake for another 5-7 minutes until lightly golden. Let it cool.

Whisk the Eggs and Sugar: In a medium saucepan, whisk together the eggs, sugar, lemon zest, and lemon juice.

Cook Over Low Heat: Place the pan over low-medium heat, stirring constantly until the mixture thickens (about 5-7 minutes).

Incorporate the Butter: Remove from heat and whisk in the melted butter until smooth.

Strain for a Silky Texture: Pass the curd through a fine-mesh sieve to remove any cooked egg bits.

Pour the Curd into the Tart Shell: Spread the lemon filling evenly into the pre-baked crust.

Bake Again: Return to the oven and bake at 325°F (160°C) for 10-12 minutes until the edges are set but the center still has a slight jiggle.

Cool and Chill: Let the tart cool completely before refrigerating for at least 2 hours to set.