Preheat the oven to 350°F. Lightly grease and flour two 9-inch cake pans to prevent sticking.
In a large mixing bowl, whisk together the flour, baking powder, salt, cocoa powder, and espresso powder to evenly distribute the dry ingredients.
In a separate medium bowl, mix the olive oil and granulated sugar until well combined. Using a hand or stand mixer, beat in the eggs one at a time, ensuring each is fully incorporated before adding the next.
Stir in the vanilla extract, followed by the buttermilk and red gel food coloring, mixing until the batter takes on a uniform color.
With the mixer on low, gradually add the dry ingredient mixture to the wet ingredients, alternating additions and starting and ending with the dry mix.
In a small cup, combine the vinegar and baking soda. Once it begins to fizz, immediately fold it into the cake batter.
Evenly divide the batter between the two prepared cake pans and bake for 25 minutes, or until a toothpick inserted in the center comes out clean.
Let the cakes cool in the pans for about 10 minutes, then carefully transfer them onto an oiled wire rack to cool completely.
Once cooled, wrap the cakes in plastic wrap and refrigerate for a few hours to allow them to firm up before frosting.