
In a large bowl, whisk together the flour and salt. With a pastry cutter, cut in the butter until only pea sized pieces remain. You can also use a food processor to do this.
Add 4 tablespoons of water and mix, add the water a little more at a time until the dough is shaggy and sticks together. Form into a flat disc and cover with plastic wrap. Chill in the refrigerator for at least 2 hours.
Once the dough is ready, roll into ⅛” thickness and cut into 4” circles. Press into the cavities and up the sides of a 12-count muffin tin.
Preheat the oven to 400°F (200°C), or 180°C if you have a fan oven.
In a medium bowl, whisk together the corn syrup, brown sugar, butter, egg, vanilla, cornstarch, cinnamon, salt and nutmeg until smooth.
If using raisins, divide them among the chilled tart shells first. Then add the filling to the tart shells, only filling about 1/2 way.
Bake in the preheated oven for 5 minutes, then reduce the heat to 350 and bake an additional 15-20 minutes, or until the filling is bubbling and the crust is golden.
Allow to cool for at least 15 minutes before using a butter knife to help remove them from the pan.