1 tsp vanilla extract or the seeds from ½ a vanilla bean
1/2 cup golden raisins
In a mixer fitted with a paddle attachment, combine flour, sugar and salt. Cut the cold butter into small pieces (pull butter from the fridge 30 minutes before adding) and add to the flour, mix until dough is rough, crumbly texture. Add egg and water at once and whisk, mixing until dough forms. Shape the dough into 2 logs, warap in plastic and chill at least an hour.
Preheat the oven to 200 degrees Celcius) and lightly grease a 12 cup muffin tin with butter. Lightly dust a work surface with flour and unwrap pastry logs. Slice each log into six equal pieces. Roll each piece to about 1/4in thickness and line each muffin cup (you can trim the crust, or leave the ruffle of pastry for a pretty effect once it bakes). Chill lined muffin tray while preparing filling.
Whisk sugar, corn syrup and butter in a bowl by hand until combined. Whisk in the eggs, then add the vinegar and vanilla or vanilla bean seeds. Sprinkle a few raisins in the bottom of each muffin cup and pour the filling over the raisins.
Bake the tarts for 5 minutes, then reduce the heat to 190 degrees Celcius. Continue baking until butter tart filling starts to rise and form a dome after about 20 more minutes. Remove from the oven and allow tarts to cool before removing them from the tin.