**Prep**: Preheat the oven to 350°F. Line and butter three 8-inch round pans.

**Dry Ingredients**: In a bowl, whisk together flour, baking powder, baking soda, granulated sugar, brown sugar, and salt.

**Wet Ingredients**: In another bowl, whisk together eggs, vegetable oil, buttermilk, and sour cream until smooth.

**Combine**: Gradually add dry ingredients to the wet mixture, stirring until just combined.

**Cocoa Mixture**: In a small bowl, mix cocoa powder and instant coffee with boiling water until smooth. Add to the batter and gently fold in.

**Bake**: Divide the batter evenly among the prepared pans. Bake for 22-24 minutes, until a toothpick comes out with moist crumbs.

**Cool**: Let cakes cool in the pans for 20 minutes, then transfer to a wire rack to cool completely. Refrigerate for 1 hour.

**Melt Chocolate**: Melt dark chocolate and corn syrup over low heat, stirring constantly. Set aside.

**Mix Base**: In a mixer, beat cream cheese, cocoa powder, powdered sugar, and salt until creamy.

**Add Cream**: Add chilled heavy cream and beat until fluffy.

**Combine**: Slowly add melted chocolate to the mixture while beating on low speed until fully combined. Let the frosting cool until spreadable.

**Trim**: Trim the domes off the cooled cakes with a serrated knife.

**Layer**: Stack the cakes with a generous layer of frosting between each. Apply a thin crumb coat of frosting and refrigerate for 20 minutes.

**Frost**: Cover the cake with the remaining frosting.

**Serve**: Enjoy the cake at room temperature. For a shiny finish, gently wave a blow dryer 1 foot away from the cake on the lowest setting.