Gradually add the oil while mixing constantly until the mixture is smooth.
Add the buttermilk, ½ of the flour, baking soda, and baking powder, and mix until almost combined. Add the other ½ of the flour and mix until just combined, and there are no visible lumps of flour.
Pour the batter into the prepared baking pans and bake the cake in a 180°C (350°F) preheated oven for about 25-30 minutes or until a toothpick inserted into the cake comes out clean with a few moist crumbs.
Allow the cake layers to cool completely. Run a butter knife or a thin spatula around the edges of the cake to release it from the sides of the pan.
Invert and Tap: Place a wire rack or plate over the pan, hold them firmly, and flip to invert the pan. Lift Gently: Carefully lift one side of the pan, then remove it completely to slide your cake onto the surface.
Make the chocolate frosting
In a medium mixing bowl, add the powdered sugar and room temperature butter, sift the cocoa powder, add the vanilla extract and salt, and whip with an electric hand mixer for 1-2 minutes.
Then, add the melted and cooled dark chocolate. Mix on high until the frosting is whipped and smooth.
Assembly
Pipe a small dollop of the frosting on the surface that you will frost on. Lay the first cake layer over the frosting dot.
Top the first cake layer with about ⅓ of the frosting and spread an even layer using a spatula.
Top it with the second cake layer. Frost the cake with the remaining frosting and make a wave pattern using an offset spatula.
If it seems like it's too much frosting, feel free to remove some and save it for your next chocolate cake.
Notes
Use room temperature ingredients. It is important that you use room-temperature ingredients like eggs and butter. This step ensures that your mixture mixes into a homogenous mixture and bakes perfectly.
Measure your flour correctly! When measuring your flour, avoid scooping it with a measuring cup. Instead, stir the flour with a spoon to create as many air pockets as possible, and spoon it into your measuring cup. Finally, level it with a back of a knife.
Don’t overmix the cake batter, you don’t want to develop the gluten in the flour. This step ensures you have a moist cake and not a dense and dry cake.
Make sure that you are using fresh ingredients like baking soda and baking powder. If they are expired your cake will not rise up beautifully.
Line your baking pan with parchment paper! This step helps the cake to bake evenly, and it makes sure that your loaf cake will release easily from the pan.
Use cake strips!Cake strips give you even and perfectly baked cake layers. Click here for the Amazon link.
If your frosting seems too soft for spreading, place it in the refrigerator for about 30 minutes to firm up slightly before using it on the cake.
Test for doneness carefully. Insert a toothpick into the center, it should come out clean or with just a few crumbs attached when done.
Be patient! I know it’s extremely tempting to frost this cake as it is pulled out of the oven, but let the cake cool for at least 1 hour so it will be firmer and won’t crumble up, and prevent the frosting from melting.
Serve at room temperature for optimal taste. Bring the cake to room temperature before serving to ensure that the frosting is creamy and not hard and will melt in your mouth.