Line a large baking sheet with parchment paper. Roll a vol-au-vent shell on a lightly floured surface into 5-inch wide round. Place on the baking sheet. Repeat with remaining vol-au-vent. Top the rounds with half the cheese. Top the cheese on each tart with 4 slices of tomato, and then season with pepper. Top the tomatoes with the remaining cheese. Chill the tarts in the fridge for 15 minutes. Preheat the oven to 375 degrees F. Bake the tarts for 20 to 25 minutes, or until puffed and golden. Serve warm or at room temperature topped with the torn fresh basil leaves.