How to Make It
Preheat oven to 350°F. Lightly coat 3 (9-inch) round cake pans with baking spray.
Combine chocolate chips and hot coffee in a medium bowl; let stand 2 minutes. Stir until chocolate is melted, about 1 minute. Whisk in oil, sour cream, eggs, and vanilla until smooth.
Stir together flour, sugar, cocoa, salt, baking soda, and baking powder in a large bowl. Stir in wet ingredients. Divide batter evenly among prepared pans (about 2 cups per pan).
Bake in preheated oven until a wooden pick inserted in center comes out clean, 20 to 25 minutes. Let cool in pans 10 minutes. Invert cake layers onto wire racks, and let cool completely, about 1 hour.
Spread frosting between layers and on top of cake. Spread a thin layer of frosting on sides of cake, smoothing with a spatula. Chill cake 30 minutes. Spread an additional layer of frosting on top and sides of cake.