Crisp meringues, tangy orange curd, and rich whipped cream come together in one sensational dessert. Martha made this recipe on episode 612 of Martha Bakes.
Preheat oven to 300 degrees. Use a 3-inch bowl to trace 6 circles on each of 2 sheets of parchment paper. Transfer each sheet of parchment paper to a baking sheet tracing-side down.
In the bowl of an electric mixer fitted with the whisk attachment, beat egg whites and salt together until glossy peaks form. With mixer running, add sugar in 3 additions, beating until meringue is stiff and glossy. Sprinkle in cornstarch, vinegar, and vanilla. Gently fold to combine.
Fill a pastry bag fitted with a large plain round tip, about 5/8 inch in diameter. Pipe a mound of meringue in the center of each of the circles. Use the back of a spoon to create an indentation in the center of each mound. Transfer baking sheets to oven and immediately reduce the temperature to 250 degrees. Bake until firm and dry to the touch but not browned, 30 to 35 minutes. Turn off oven and let meringues cool for 20 minutes. Remove to a wire rack to cool completely.
Make curd: Combine yolks, sugar, orange zest, orange juice, lemon juice, salt, and butter in a heavy-bottomed saucepan; whisk to combine. Cook over medium-high heat, stirring constantly with a wooden spoon or heatproof spatula (be sure to scrape the sides of the pan), until the mixture is thick, 8 to 10 minutes. Let mixture come to a rapid simmer and cook, continually scraping sides of pan, for 2 minutes. If desired, strain through a fine sieve into a medium bowl. Cover with plastic wrap, pressing it directly onto the surface of the curd to prevent a skin from forming. Refrigerate until chilled and very firm, at least 2 hours or up to 1 1/2 weeks.
Make topping: Whisk heavy cream until stiff peaks form. Top meringues with a dollop of curd and whipped cream and if desired, serve with orange segments.