1. Begin by putting all the dry ingredients into a food processor as well as the butter and pulse the mix until it resembles fine breadcrumbs. You can also use the rubbing
methods if you do not have a food processor.

2. Next add in the egg yolk and 1 tbsp of water to begin with, pulse a few times and continue adding water till the dough comes together. Don't add too much water. 

3. Tip your mixture onto a clean work surface and continue to bring it together with your hands so that it forms a ball.

4. Wrap with cling film and then chill in the fridge for 30 minutes or freezer for 15.  

5. Once the pastry has chilled dust a clean work surface with flour and roll out the dough to the thickness of a £1 coin. Fold the dough in half and then place it onto half of an 8–9-inch tart dish, unfold the rest of the dough over so that it ends up covering the whole tin. Press the pastry into the bottom and up the tin and cut off the excess leaving ½ a cm over the edge to prevent shrinkage. Then allow that to chill in the freezer for a further 15 minutes. 

6. Now that the pastry is made begin making the filling; place the egg yolks in a large bowl and begin whisking while pouring in the condensed milk. Once that is mixed add the lemon zest and while whisking stream in the lemon juice until everything is fully combined. 

7. Pour the filling into the pasty case and bake in an oven pre heated to 140 degrees c/fan for 15 minutes.

8. When the pie has finished baking allow to cool until cool to the touch and then place in the freezer for 15-25 minutes till cold. 

9. To make the meringue combine the sugar and egg whites in a bowl and whisk over abain-marie until the sugar is dissolved. Transfer to a mixer and whisk until the meringue is glossy, stiff and cool.

10.Finally take the pie out of the freezer and pipe or dollop the meringue on top of the pie. Using a blow torch (with adult supervision) or a grill, toast the top of the meringue and the VOILA serve and enjoy.