Preheat oven to 350 degrees. Grease an 9-inch spring form pan with a bit of olive oil. Line the bottom with parchment paper, and grease the paper.
In a large, microwave-safe bowl, melt together the chocolate and olive oil for 30 seconds; stir very well, then return to the microwave in 10 second bursts, if needed, until fully melted.
In the bowl of an electric mixer fitted with the paddle attachment, mix together the chocolate/olive oil mixture, and the sugar and salt until cool. Add in the eggs one a time, mixing well after each addition. Add in the cocoa powder and mix until combined. Scrape into the prepared pan. Rap it a few times on the counter to release any air bubbles.
Bake for 25 minutes, or until a toothpick inserted into the center comes out with just a few moist crumbs clinging to it. Allow to fully cool before removing from pan and peeling off the parchment from the bottom. Sift confectioners’ sugar over top, and serve with crème fraîche.