In a large bowl, use an electric mixer or whisk attachment on medium speed to beat together the olive oil, sugar and brown sugar, scraping down the bowl a few times, until the mixture comes together into small clumps and looks like crystals. Turn the mixer to low speed and, with the mixer on, add the eggs, one at a time, and beat well after each addition. Stop the machine and scrape down the bowl as needed. Add the tahina and vanilla and whisk again. Add the flour, cocoa, baking powder and salt and whisk well. Add the chocolate chips and mix to distribute.

Place the dough into the fridge for one hour to firm up.  Preheat oven to 400ºF.

Line three baking sheets with parchment paper, or bake in batches. Cover and refrigerate the dough between batches. Scoop up a heaping tablespoon of dough and use another spoon to drop the dough on the prepared baking sheets, about two inches apart. I like to use a small cookie scoop. Press the tops down to flatten the ball. Try to make sure all your cookies are the same size.

Bake the cookies for 12 to 14 minutes, until the cookies are mostly set but the centers are still soft; when you press the centers, your finger should be able to press halfway down into the cookie. The bottoms should not be too firm. Use a spatula to immediately lift the cookies onto a wire rack and let cool. Store at room temperature in an airtight container for up to five days or freeze for up to three months.