Preheat oven to 425 degrees.

To make the pie crust: In a bowl combine flour, sugar, salt and shortening with a pastry blender or your hands until it's all incorporated. Add the egg yolk to a measuring cup, then add enough milk to make 2/3 cup. Whisk together. Pour the egg/milk mixture into the flour mixture and combine with your hands. The dough will be a little sticky. Form dough into a ball. Place dough ball on a floured surface and roll out into a rectangle measuring about 19x14". Carefully fold the dough into sixths to make it easier to move onto a 15x10x1" sheet pan. Trim crust at the pan's edge and form a crust edge. Prick holes into the bottom and sides of the crust with a fork. Bake for 10-15 minutes, or until light golden brown. Remove and let cool.

Reduce oven to 325 degrees.

Prepare the custard: Whisk egg yolks in a mixing bowl. Add to them the condensed milk, lime juice and lime zest. Mix well, and spread into cooled pie crust. Bake for 20 minutes, until custard is set. Cool on the counter for about 30 minutes then place in the fridge for about 3 hours.

Whip cream and powdered sugar with your mixer, with a whisk attachment until stiff peaks form. Spread over the custard. Garnish with lime slices and zest, raspberries if desired.

Keep in the fridge.