1. Cut the butter into the flour using a pastry cutter until the mixture resembles coarse breadcrumbs.

2. Stir in the sugar and salt. Add the egg and mix with a fork until just combined, then use your hands to form a dough.

3. Roll the dough on a floured surface to 1/8-inch thick.

4. Cut into rounds with a cookie cutter and press into mini muffin tins.

5. Freeze for 30 minutes to prevent shrinking.

6. Bake at 350°F for 20 minutes or until golden. Cool completely.

7. Heat lemon juice over medium heat until hot but not boiling.

8. Whisk eggs and yolk in a bowl. Gradually whisk in sugar.

9. Slowly pour hot lemon juice into egg mixture while whisking constantly.

10. Return mixture to saucepan and cook over medium heat, stirring constantly, until thickened to 170°F.

11. Remove from heat and stir in butter until melted. Add cream, vanilla, and salt.

12. Spoon lemon curd into cooled tartlet shells.

13. Top with berries if desired and chill slightly before serving.