This red, white, and blue dessert is the perfect treat to serve on the Fourth of July.
Using a 3-inch bowl or cookie cutter, draw 8 circles on a sheet of parchment paper. Turn the paper over, and place on a baking sheet; set aside.
Preheat oven to 200 degrees. In the bowl of an electric mixer fitted with the whisk attachment, combine whites, lemon juice, and vanilla. Beat on medium-low speed until soft peaks form, about 1 1/2 minutes. Reduce to low speed, and gradually sprinkle sugar over whites. Increase speed to high and beat until stiff glossy peaks form, 2 to 3 minutes. Remove from mixer; sift cornstarch over, and fold to combine.
Fit a pastry bag with a plain pastry tip with a 1/2-inch opening (Ateco No. 6), and fill bag with meringue. Beginning in the center of one of the circles, cover with an even layer of meringue. Pipe around the perimeter to form a 1-inch collar. Repeat process with remaining circles.
Transfer baking sheet to oven, and bake for 1 hour. Reduce heat to 175 degrees, and bake until meringue has dried but is still white, about 1 hour more. Transfer to a wire rack to cool.
Place a meringue on a dessert plate. Fill with a scoop of sorbet, and drizzle with blueberry sauce. Serve immediately.