Preheat oven to 375 degrees Fahrenheit.

In a mixing bowl, combine brown sugar and melted butter.

Stir in vanilla extract, vinegar, and lemon juice.

In a separate bowl, lightly beat the eggs.

Add the beaten eggs to the butter mixture and stir in corn syrup until well combined.

Place 5 or 6 raisins, chopped walnuts, or pecans into the bottom of each tart shell.

Carefully pour the filling into each tart shell, filling them about 2/3 full.

Bake in the preheated oven for approximately 20 minutes, or until the filling is just barely set.

Remove from oven and let cool completely before serving.