Add the icing sugar, butter, vanilla & salt in the bowl of a stand mixer fitted with a paddle attachment.
Beat the mixture on a medium speed for a few minutes until it forms a paste. Scrape down the bowl halfway through.
Slowly add in the flour, and mix on low speed until it is just combined. The mixture will look crumbly. Don't worry as it will come together when rolled and rested.
Transfer the mixture on a lightly floured surface. You will want to divide the dough into 2 batches to make rolling out easier.
Place a large piece of parchment paper down, lightly flour it, and place one batch of dough on top. Sprinkle the dough lightly with flour and place another large piece of parchment paper over the top
Roll the dough out with a rolling pin to 3mm (1/8 inch). I have a rolling pin with training wheels on the side that tells me exactly what 3mm is but you can eyeball it. 3mm is two pennies thick.
Place the whole sheet of pastry in the fridge for 30 minutes. Repeat the above steps with the second batch of dough if divided.
Once the dough has chilled, remove one sheet from the fridge. Peel off the top sheet of parchment paper, very lightly flour the pastry, then flip it over.
Peel off the remaining sheet of parchment paper, lightly flour the dough again to prevent it from sticking.
Cut out the dough using a 5.75" oval perforated tart ring. Peel off the excess dough and you can re-roll this for another use. You can use different dimensions if you have different tart forms.
Remove the second sheet of dough from fridge. Using a sharp knife, cut long strips of dough about 7-8” long and ¾” wide.
Carefully lift the strips and place them on the inside of the tart rings. Press them against the side so they line up with the dough at the bottom.
Press the bottom of the dough gently with your fingers to mold it to the base of the dough.
Cut off any excess pastry hanging over the top of the tart rings with a sharp knife.
Place the tart shells into the freezer for 30 minutes to 1 hour.
Pre-heat your oven to 320F. Place the tray with your tart shells in the oven. Bake for 15 minutes or until the shell is lightly golden.
Remove tart shells from the oven and allow time to cool before piping so the filling does not melt.