Within the bowl of a stand mixer fitted with the paddle attachment or utilizing a big bowl and a handheld mixer, beat the brown and granulated sugars, oil and butter on medium velocity till lightened in colour, creamy and fluffy, about 2 minutes, scraping down the edges and backside of the bowl and attachment as wanted. Nonetheless on medium, beat within the vanilla extract, then the eggs, one after the other, ready till the primary is integrated earlier than including the second. Scrape down the bowl once more. On low velocity, step by step add half the cocoa powder combination. The batter could look separated or curdled, however to not fear. After the liquid has been totally blended in, cease the mixer, add half the flour combination and blend once more on low till the dry elements are integrated. Repeat with the remaining cocoa combination after which the remaining flour combination.
