Vanilla-Scented Cornmeal Cake with Olive Oil Buttercream

Make buttercream

In bowl of a stand mixer, whisk sugar, egg whites, salt, and cream of tartar. Set bowl over a large saucepan of barely simmering water. Cook egg whites mixture, whisking gently and constantly, until sugar is completely dissolved, mixture is hot, and an instant read thermometer registers 185°F when placed in center of mixture, about 8 minutes (some of mixture may dry along edges of bowl).

Transfer bowl to a stand mixer fitted with a whisk attachment. Beat on high speed until whites form firm, glossy, stiff peaks, and bowl has cooled to touch, about 5 minutes. With mixer on medium-high speed, add butter one piece at a time, beating to blend between each addition and stopping about

 halfway through adding butter to scrape down bowl, until all butter has

 been fully incorporated and mixture is smoothly emulsified, silky, and fluffy. Scrape down sides and bottom of the bowl. Add olive oil and citric acid (this adds acidity and balances the flavor) and beat until just combined. Season to taste with salt, if desired. Frost cake with buttercream and decorate with edible flowers, if desired.

Ideas for decorating the cake

Keep a pitcher of warm water on side for cleaning your spatulas (preferably one small and one large offset spatula) as needed while decorating the cake. Spread 1/2 cup of frosting over top and sides of cake

 (This is called a crumb coat; the layer will be thin). Smooth any ridges that may form along the edges. Refrigerate cake until set, about 15 minutes.