Juice and zest lemon and set aside.
In a small saucepan, combine the egg yolks, granulated sugar, and a pinch of salt. Whisk on medium heat for 1 minute or until there is no grain to the mixture.
Add the lemon juice and cook for another minute whisking to combine.
Next, add the lemon zest and using a silicone spatula stir the mixture until thickened on low heat for 10 minutes. Be sure to continue stirring to keep the smooth velvety texture.
After the mixture has thickened remove it from the heat and stir in the butter and vanilla extract until combined and silky in texture. Allow the lemon curd filling to cool.
IF USING FROZEN TART SHELLS: While the lemon curd is cooling, bake pastry shells according to package directions and allow them to cool on a cooling rack.
Fill cooled tart shells using a medium cookie scoop or with about a tablespoon and a half of the lemon curd filling.
Serve at room temperature if you are in a rush but for best results chill them for at least one hour and enjoy! Garnish with berries and a dusting of powdered sugar or whipped cream.
