In a food processor, combine Truvia Baking Blend and cornstarch. Process on high speed until mixture resembles the consistency of confectioners' sugar. Remove from processor; set aside.
Using a hand mixer with the whisk attachment, mix together meringue powder with water until soft peaks form, about 1 minute. Using the beater attachments, add Truvia mixture; continue mixing until well combined, scraping down sides of the bowl as necessary.