3/4 cup finely diced seeded plum tomatoes (about 2)
1 small shallot, minced
1/2 tablespoon olive oil
1 teaspoon champagne or white wine vinegar
1/2 teaspoon chopped fresh thyme
2 to 3 grinds of black peppercorns
1 sheet frozen puff pastry dough, thawed
Cooking spray or parchment paper
1/3 cup finely grated Parmesan cheese
Kosher salt to taste
Fresh small basil leaves for garnish (optional)
Preheat oven to 400 degrees F.
Combine the first 6 ingredients in a medium bowl. Place the sheet of pastry dough on a work surface lightly dusted with flour. Cut the dough with the 1 1/2-inch heart cutter into about 20 pieces. Place on a baking sheet coated with cooking spray or a piece of parchment paper. Top each heart with a small amount of cheese and a small amount of the tomato mixture.
Bake at 400 degrees F. for about 15 minutes or until golden. Sprinkle tarts evenly with salt. Sprinkle with basil leaves, if desired