Place the flour and salt in a bowl and stir to combine.
Add in the cubed butter and with a pastry cutter or fork, knead the butter into the flour until the mixture resembles large breadcrumbs.
Make a well in the center and add in the egg yolk, apple cider vinegar and ? cup of the ice water and mix until a dough begins to form, adding a tablespoon amount of ice water at a time, as needed, for the mixture to hold when pressed together.
Shape into a disc shape, cover and refrigerate for minimum of 1 hour, until well chilled.
Once the dough is well chilled, remove from the fridge and place onto a lightly floured surface.
Roll the pastry out to ¼ inch thickness and with a pastry or round cookie cutter, to fit into your tart or muffin tin.
Press into your pans firmly from the base upwards. Cut away any excess dough that sits well above the muffin cups.
Place in the freezer for a minimum of 30 minutes.
Meanwhile, preheat the oven to 180°C/360F.
Cover the frozen tarts with aluminum foil and fill with baking beans or rice right up to the top edge of your pastries.
Place in the oven and bake for approximately 15 minutes, remove the foil and beans or rice and cook for a further 10 minutes until golden.
Remove and allow to cool to room temperature.