Step 1: Preheat your oven to 350°F (175°C). Grease and flour three 8-inch round cake pans, or line with parchment paper.
Step 2: In a large bowl, whisk together the all-purpose flour, granulated sugar, unsweetened cocoa powder, baking soda, baking powder, and salt. Make sure there are no lumps.
Step 3: In a separate medium bowl, whisk together the buttermilk, vegetable oil, eggs, and vanilla extract until well combined.
Step 4: Gradually add the wet ingredients to the dry ingredients, mixing on low speed until just combined. Do not overmix.
Step 5: Slowly pour in the hot coffee (or espresso), mixing until the batter is smooth. The batter will be thin, this is normal.
Step 6: Divide the batter evenly among the three prepared cake pans.
Step 7: Bake for 25-30 minutes, or until a wooden skewer inserted into the center comes out with moist crumbs.
Step 8: Let the cakes cool in the pans for 10 minutes before inverting them onto a wire rack to cool completely. This is crucial before frosting to prevent the cake from crumbling or melting the frosting.
Step 9: In a large heatproof bowl set over a saucepan of simmering water (bain-marie), combine the unsweetened chocolate, unsalted butter, and powdered sugar. Stir occasionally until melted and smooth. Remove from heat.
Step 10: Whisk in the heavy cream and vanilla extract until the mixture is smooth and glossy.
Step 11: Allow the fudge frosting to cool slightly at room temperature, then chill in the refrigerator for about 30-45 minutes, stirring occasionally, until it reaches a spreadable consistency. It should be thick but not too firm. This helps make sure your Decadent Chocolate Fudge Layer Cake with Caramel Drizzle is irresistible! frosting holds its shape beautifully.
Step 12: In a heavy-bottomed saucepan, combine the granulated sugar and 1/4 cup water. Stir gently to dissolve the sugar.
Step 13: Cook over medium heat without stirring until the sugar dissolves and the mixture begins to boil. Once boiling, stop stirring.
Step 14: Continue to cook, swirling the pan occasionally, until the syrup turns a rich amber color. This can take 8-10 minutes. Watch it carefully; it can burn quickly!
Step 15: Carefully and slowly pour in the warm heavy cream while whisking constantly. The mixture will bubble vigorously. Continue whisking until smooth.
Step 16: Remove from heat and stir in the unsalted butter and sea salt until fully incorporated and smooth.
Step 17: Let the caramel cool completely to room temperature. It will thicken as it cools. If it gets too thick, you can gently warm it over low heat for a few seconds. This salted caramel really elevates the Decadent Chocolate Fudge Layer Cake with Caramel Drizzle is irresistible! flavor profile.
Step 18: Once the cake layers are completely cool, place one layer on your serving plate or cake stand.
Step 19: Spread about 1/3 of the fudge frosting evenly over the top of the first layer.
Step 20: Place the second cake layer on top and repeat with another 1/3 of the frosting.
Step 21: Top with the third cake layer and spread the remaining frosting over the top and sides of the cake, smoothing it out with an offset spatula.
Step 22: Drizzle the cooled salted caramel generously over the top of the cake, allowing it to drip down the sides for a beautiful effect. You can use an airtight glass container to store any leftover caramel for later use.
Step 23: For best results, chill the cake for at least 30 minutes before serving to allow the frosting and caramel to set.