In the heatproof bowl of a stand mixer, whisk together sugar, egg whites, cream of tartar, and salt. Place bowl over a saucepan of simmering water and cook, whisking frequently, until sugar completely dissolves and an instant-read thermometer registers 120° to 130°.
Carefully return bowl to stand mixer. Using the whisk attachment, beat at high speed until stiff peaks form, 2 to 3 minutes. Beat in vanilla. Use immediately.
*We used an Ateco 807 decorating tip
Recipe by Southern Lady Magazine at https://southernladymagazine.com/mini-mango-cheesecake-trifles/