1. Lightly spray 18 muffin tins.
2. Roll out Buttery Pastry to about 1/8 inch (5 mm) thick and cut out 4 inch (10 cm) circles to fit muffin tins. Gather scraps and roll out again to cut out more circles to get 18 tart shells. Refrigerate for about 15 minutes or until chilled.
3. Preheat oven to 350ºF (180ºC).
4. In a large bowl, using a hand mixer, beat together cane sugar, maple syrup, butter, eggs, vinegar and salt until smooth.
5. Divide walnuts and currants among chilled tart shells. Pour the butter mixture evenly into tart shells.
6. Bake for 20 to 25 minutes or until pastry is light golden and filling is golden. Remove from oven and run a small knife around edges of tarts. Let cool completely in muffins tins on a rack.
Tip: Store in an airtight container for up to 5 days at room temperature or freeze for up to 2 weeks.