Preheat the oven to 325°F. Lightly spray your round cake pan with cooking spray and line it with parchment paper.
In a medium bowl, combine the sugar, flour, cocoa powder, powdered sugar, chocolate, and salt.
In a large bowl, whisk together the eggs, olive oil, heavy cream, and vanilla.
Sprinkle the dry mix over the wet mix and stir until just combined.
Pour the batter into the prepared pan and use a spatula to smooth the top.
Bake for 40 to 48 minutes, or until a toothpick comes out with only a few crumbs attached.
Cool completely before slicing.