Assemble Ankarsrum mixer with beater bowl and balloon whisks. Add egg whites, cream of tartar, and salt. Beat at medium-low speed (3 o’clock) until foamy, 2 to 3 minutes. Add sugar in a slow, steady stream, beating until combined (3 to 5 minutes total). Increase mixer speed to medium-high (6 o’clock), and beat until thick and shiny, 8 to 10 minutes. Rub meringue between 2 fingers to make sure it is smooth and no sugar granules can be felt. Add vanilla, and beat at medium-high speed (6 o’clock) until combined, about 30 seconds.

Preheat oven to 225°F (105°C). Line 2 baking sheets with parchment paper.

Transfer meringue to a large pastry bag fitted with a ½-inch French star piping tip (Ateco #867). With tip perpendicular to parchment paper, pipe 1¼-inch-wide, 1-inch-high kisses at least ½ inch apart on prepared pans. (Feel free to make smaller kisses, if desired.)

Bake until meringues are dry to the touch and easily peel away from parchment, 45 minutes to 1 hour. Turn oven off, and leave kisses in oven with door closed for 1 hour. Remove from oven, and let cool completely on pans. Store in an airtight container for up to 2 days.

In the bowl of a stand mixer fitted with the whisk attachment, beat egg whites, cream of tartar, and salt at medium-low speed until soft peaks form, 5 to 6 minutes. With mixer on low speed, add sugar in a slow, steady stream, beating until combined. (This should take about 3 minutes.) Increase mixer speed to medium, and beat until thick and shiny, 10 to 12 minutes, stopping to scrape sides of bowl halfway through mixing. Rub meringue between 2 fingers to make sure it is smooth and no sugar granules can be felt. Add vanilla, and beat at medium-high speed until combined, about 30 seconds.

Preheat oven to 225°F (107°C). Line 2 baking sheets with parchment paper.

Transfer meringue to a large pastry bag fitted with a Wilton 1A round piping tip. Holding tip perpendicular to parchment paper, pipe 1¼-inch-wide, 1-inch-high meringue kisses at least ½ inch apart on prepared pans.