Bursting Blueberry Lemon Thyme Tarts

Bahan-bahan (4 porsi)

• 2 1/2 -3 cups fresh or frozen blueberries
• 1 -2 tablespoon cornstarch ((see notes))
• 1/4 cup honey or granulated sugar
• 1 tablespoon lemon zest + 1 teaspoon lemon juice
• 1 tablespoon fresh thyme leaves ((or 2 teaspoons dried thyme))
• 1 teaspoon vanilla extract
• 1 sheet frozen puff pastry, thawed
• 1 egg, beaten
• coarse sugar, for sprinkling ((optional))
• vanilla ice cream, for serving ((optional))