Blueberry-Coriander Buttercream Frosting

Whisk together egg whites and sugar in a heatproof bowl or bowl of a stand mixer. Place the bowl over a saucepan of simmering water over medium-low. Cook, whisking constantly, until sugar is dissolved and a thermometer inserted in mixture registers 160°F, about 6 minutes. 

Transfer bowl to stand mixer fitted with the whisk attachment, and beat on high speed until stiff, glossy peaks form and meringue is at room temperature, 10 to 15 minutes. Turn off mixer, and scrape down sides of bowl. With mixer running on medium speed, gradually add butter, 1 tablespoon at a time, beating well after each addition. Continue to beat until mixture is light and fluffy, 8 to 10 minutes. Scrape down sides of bowl. With mixer running on medium speed, beat in strained jam and salt until just combined, about 1 minute.