Mix the grapeseed oil with zest of one blood orange and set aside.
Preheat oven to 350°F. Grease the bottom and sides of a 9-inch cake pan with 2 tablespoons of butter. Sprinkle 3 tablespoons of organic cane sugar on bottom of pan, tilting the pan to get an even coating of sugar, avoiding the sides. Layer the sliced blood oranges on the bottom of the pan.
Sift the all-purpose flour, cane sugar, cocoa powder, baking soda, and salt together in a large mixing bowl. Make a well in the middle.
Mix the coffee, grapeseed oil with orange zest, apple cider vinegar, and vanilla extract. Whisk until combined.
Pour the wet ingredients into the well of dry ingredients. Mix vigorously by hand with a whisk until smooth. Stir in the chocolate chips if desired. Pour batter into the greased cake pan.
Bake for approximately 45 to 55 minutes or until a toothpick inserted into the center comes out with crumbs clinging to it.
Let the cake cool for at least 30 minutes before gently flipping it onto a cooling rack. Loosen the edges first with a butter knife or a plastic knife.
Notes
Calorie calculation is done without chocolate chips.
If you are using an 8-inch cake pan, the baking time may be slightly longer.
Let the cake cool completely before storing it in the fridge. Store in fridge for up to 5 days in a covered container.
If your oranges are especially juicy the baking time may take a bit longer than the recommended time. Check for doneness every 5 minutes.
To make this cake fudgier and even more chocolatey, double the amount of cocoa powder and add the chocolate chips!