1. Make the Tartlet Shells

1. In a mixing bowl, combine flour and powdered sugar.
2. Add cold cubed butter and rub it into the flour using your fingertips until the mixture resembles coarse crumbs.
3. Stir in the egg yolk and 1 tablespoon cold water, mixing until a dough forms. Add more water if needed.
4. Shape the dough into a disc, wrap in plastic wrap, and refrigerate for 30 minutes.

2. Shape & Bake the Tartlets

1. Preheat oven to 350°F (175°C).
2. Roll out the chilled dough on a lightly floured surface to about ⅛-inch thickness.
3. Cut out circles slightly larger than the tartlet molds and press them into the tins.
4. Prick the bottoms with a fork and chill for 10 minutes.
5. Bake for 12-15 minutes, or until golden brown. Let cool completely.

3. Make the Lemon Curd

1. In a saucepan over medium-low heat, whisk together lemon juice, lemon zest, sugar, and eggs.
2. Stir continuously while adding cubed butter.
3. Cook for 8-10 minutes, stirring constantly, until thickened.
4. Strain through a fine mesh sieve for an ultra-smooth curd.
5. Let cool slightly before filling the tartlets.

4. Fill & Chill the Tartlets

1. Spoon the lemon curd into the cooled tartlet shells.
2. Smooth the tops and refrigerate for 1-2 hours until set.

5. Garnish & Serve

1. Dust with powdered sugar or top with fresh berries.
2. Serve chilled and enjoy!