This rustic chocolate cake is made with two surprising ingredients: olive oil and lemon juice. Extra-virgin olive oil lends fruity, peppery flavor notes. For a less prominent flavor, use light olive oil (“light” indicates the oil is refined, not lower in fat). You could even use a combination of oils—for example, a robust extra-virgin olive oil tempered with a little neutral oil. The lemon juice brings a brightness that balances the richness of the oil and chocolate, and its acidity reacts with the baking soda to provide lift. We prefer the deeper, darker color that Dutch-processed cocoa gives the cake, but natural cocoa works fine, too, if that’s what you have on hand. Serve with lightly sweetened whipped cream or with ice cream or gelato. Store leftovers well wrapped at room temperature for up to three days.