This recipe for heart-shaped meringues filled with passion fruit curd was adapted from the "Martha Stewart Baking Handbook."
Preheat oven to 200 degrees. Line a baking sheet with parchment paper. Trace 4 heart shapes onto the parchment paper using a 2 1/2-inch heart-shaped cookie cutter. Turn parchment paper over on baking sheet; set aside.
In the heatproof bowl of an electric mixer set over a pan of simmering water, combine egg whites, granulated sugar, and salt. Whisk constantly until the sugar has dissolved and the egg mixture is warm to the touch, about 2 minutes. Attach bowl to the mixer fitted with the whisk attachment; beat on medium-high speed until stiff peaks form, 2 to 4 minutes. Beat in vanilla.
Spoon meringue mixture into a pastry bag fitted with a plain round 1/2-inch tip. Cover one of the hearts with an even layer of meringue. Continue piping meringue around the outer edge of the heart, making a 1-inch-high cup. Repeat piping over the remaining hearts.
Transfer baking sheet to oven and bake 20 minutes. Reduce the heat to 175 degrees, and bake until meringue is dry and crisp but still white., 1 1/4 hours to 1 1/2 hours more. Transfer sheet to a wire rack and let meringues cool completely before carefully easing them off the parchment. Meringues can be kept in an airtight container at room temperature for up to 1 day.
When ready to serve, fill each meringue heart with passion fruit curd and garnish with berries. Dust meringues with confectioners' sugar, and serve.