Preheat oven to 400°F. On a lightly floured surface, roll the pastry out 1/4" thick. Cut out circles using a 4" cookie cutter or empty can, and press into ungreased muffin cups.

In a medium bowl, stir together the brown sugar, syrup, egg, butter and vanilla. Stir in the currants and pecans, if you're using them. Fill the tart shells about 2/3 full and bake for 20 minutes, until bubbly and golden. Take them out of the pan using a thin knife to coax them out while they are still warm, otherwise any goo that has bubbled over will stick to the pan as it cools. If it does, pop them back in the oven for a minute to soften it again. Cool on a wire rack.