Mix brown sugar, melted butter, egg, maple syrup, vanilla extract and apple cider vinegar thoroughly. Reserve.
Preheat oven to 425ºF. In a large mixing bowl, combine flour and salt. Add the butter and mix with a wooden spoon until partially blended. Add water, egg yolk and vinegar and continue combining with the wooden spoon. Once it’s easy to manipulate, place over a floured surface, sprinkle with a bit of flour and knead until soft and smooth.
Use a rolling pin to spread the dough out. Cut out 9 circles with a 4” round cutter.
Oil a muffin tray, and place the dough discs inside. They should be placed at the bottom and slightly up the edges.
Place a few raisins in each tart.
Pour the brown sugar mixture over the raisins into each tart, leaving some room at the top of the pastry.
Bake for around 15 minutes - or until filling is set. Let them cool before removing from muffin tin.