I start by preheating my oven to 350°F (175°C). Then I grease and line my cake pans with parchment paper to prevent sticking. This step saves so much frustration later.
In a large bowl, I whisk together flour, cocoa powder, baking soda, and salt. This evenly distributes the leavening and cocoa for a consistent crumb.
In another bowl, I beat the butter, oil, and sugar until light and fluffy. This step incorporates air, which helps the cake bake up soft and tender.
I add the eggs one at a time, mixing well after each. Then I blend in vanilla and black food coloring until the batter looks evenly dark.
I add the dry ingredients in three parts, alternating with buttermilk. Mixing gently here keeps the batter smooth without overworking it.
Slowly pouring in the hot liquid transforms the batter into a thin, glossy mixture. This step intensifies the cocoa flavor beautifully.
I pour the batter into prepared pans and bake until a toothpick comes out with just a few moist crumbs. Overbaking can dry it out, so I keep a close eye.
Once baked, I let the cakes cool in the pans briefly before transferring them to a rack. Cooling fully is important before frosting.