This spectacular holiday dessert comes from chef Rebecca Wilcomb's New Orleans restaurant Gianna. To decorate it, use an offset spatula, a bench scraper, and a cake turntable for the smoothest cake with straight sides. Prevent air bubbles from forming in the dark chocolate ganache glaze by using a spatula to stir the melting chocolate.
Ricotta must be drained at least 24 and up to 72 hours ahead. Cake layers may be baked 1 day ahead, individually wrapped in plastic, and chilled. Pistachio praline may be made up to 1 week ahead and stored in an airtight container. Unglazed frosted cake may be assembled and chilled overnight.