Preheat oven to 325°F (170°C). Spray 2 (6-inch) round cake pans with baking spray with flour. Line bottom of pans with parchment paper.

For cake: In a medium bowl, whisk together cocoa and hot coffee until smooth and well combined. Whisk in granulated sugar, oil, sour cream, eggs, and vanilla until smooth and combined.

In another medium bowl, whisk together flour, baking powder, and salt. Gradually add flour mixture to cocoa mixture, whisking just until combined and no dry streaks remain. Divide batter between prepared pans (about 2 cups or 520 grams each).

Bake until a wooden pick inserted in center comes out with a few moist crumbs and an instant-read thermometer inserted in center registers 200°F (93°C) to 205°F (96°C), 50 to 55 minutes. Let cool in pans for 10 minutes. Remove from pans, and let cool completely on a wire rack.

For filling: In the bowl of a stand mixer fitted with the whisk attachment, beat cream cheese, hazelnut chocolate spread, and confectioners’ sugar at low speed until smooth and combined. With mixer on low speed, add cold cream in a slow, steady stream; thoroughly scrape bowl. Beat at medium speed until light and fluffy, 2 to 3 minutes.

Level cooled cake layers, if desired. Place 1 cake layer on a cake board or serving platter. Spread filling onto cake layer, and top with remaining cake layer. Spread a thin layer of Chocolate Ganache Icing on top and sides of cake, getting icing as smooth as you can. Refrigerate until icing is set, about 15 minutes.

Spread remaining Chocolate Ganache Icing on top and sides of cake as desired. Refrigerate cake for 30 minutes before serving. If refrigerating for longer than 1 hour, let stand at room temperature for 20 to 30 minutes before serving. Before serving, garnish with Hazelnut Praline, if desired. Refrigerate in an airtight container for up to 3 days.