• Start by making the tart dough. In a food processor, add the flour, powder sugar, and salt, and mix until combined.
• Add cold cubed butter, and blend until there are pea-sized pieces of butter. If you dont have a food processor, you can do it by hand, mixing the cold butter into the flour mixture. Make sure that your hands are cold.
• Then, add the egg, and the vanilla extract and mix until a dough forms. Try not to overmix the dough.
• Cover the dough with plastic wrap and let it chill in the fridge for at least an hour.
• Transfer the dough onto a clean floured surface and roll with a rolling pin into a circle and transfer it into a 9-inch tart pan. Cut off the extra edges. Make little holes with a fork and freeze for 20 minutes.
• Bake in a 180c (350f) preheated oven for about 15-20 minutes or until the crust is a light golden brown color. Remove from the oven and let it cool while making the filling.

Make the lemon curd:

• Put all of the ingredients in a saucepan and cook it over medium-low heat whisking constantly.
• Once the butter melt, the consistency of the mixture will be thin, dont increase the heat. Keep whisking until the mixture thickens for about 5 minutes.
• When the mixture thickens, transfer it to a fine-mesh strainer set over and bowl and strain the mixture from any unnecessary lumps. This will give you a perfect and smooth curd.
• Cover the bowl tightly with plastic wrap and let the mixture cool for about 20-30 minutes.
• Pour the curd into the tart crust and smooth it out with a spatula. Bake the tart in a 180c (350f) preheated oven for about 10 minutes or until the edges are set.
• Refrigerate the tart for at least 2 hours, cut, and serve!