Start by preheating your oven to 350°F (175°C). Take two 8-inch round cake pans and lightly grease them. Line the bottoms with parchment paper, and then dust the sides with a little cocoa powder so your cakes won’t stick later.

Grab a medium bowl and whisk together your flour, cocoa powder, baking soda, baking powder, and salt. This helps everything mix evenly when you add it to the wet ingredients. Set this bowl aside for now.

In a large mixing bowl, beat together sugar, oil, sour cream, and eggs until the mixture looks smooth and creamy. Then pour in the milk and mix again until fully combined.

Chop up your chocolate and place it in a heatproof bowl. Pour hot coffee or hot water over it and stir gently until the chocolate melts completely and the mixture is silky smooth. Let it cool down for a few minutes before using it.

Slowly add your dry ingredients into the wet mixture, doing it in two batches. Alternate with the melted chocolate mixture so everything blends smoothly. Stir gently—just until combined. Avoid over mixing; you want the batter to stay light and fluffy.

Divide the batter evenly between your two prepared pans. Slide them into the oven and bake for about 28 to 32 minutes, or until a toothpick inserted in the center comes out clean.

Once baked, let the cakes rest in their pans for 10 minutes. Then carefully remove them and place them on a wire rack to cool completely. Don’t frost them while warm or the frosting will melt.

Beat softened butter on medium-high speed for about 3 minutes until it turns light and fluffy. Gradually add sifted cocoa powder and powdered sugar, alternating with heavy cream. Keep beating until the mixture becomes smooth and creamy.

Mix in salted caramel sauce, vanilla extract, and a pinch of salt. Beat for another minute or two until your frosting looks silky and spreadable. If it’s too thick, add a splash of cream; if it’s too thin, add a little more sugar.

Place one cake layer on your serving plate. Spread a generous layer of frosting on top. Gently place the second layer over it and cover the entire cake with the remaining frosting. Smooth it out with a spatula and, for an extra touch, drizzle some salted caramel sauce over the top.