Preheat your oven to 180 degrees C and note that I didn’t use any mixer here, did it by hand and it was ready in no time.
Mix all the wet ingredients in a bowl, whisking.
Sift and mix all your dry ingredients in another bowl (except the cocoa).
Whisk the dry ingredients into the wet ones.
Then move half the batter to another bowl and sift the cocoa powder into it and mix.
Line you pan with oil and flour (or cocoa) and pour the 2 batters mixing slightly so they make those pretty swirls.
Bake for 35-40 minutes, until a skewer comes out clean and enjoy. I promise you it won’t last for more than a day on your counter