Preheat your oven to 350 degrees Fahrenheit (175 degrees Celsius). Grease and flour a 9x5 loaf pan or line it with parchment paper for easy removal.
In a blender, combine the whole seedless navel orange (quartered and seeds removed), eggs, olive oil, granulated sugar, sour cream, and vanilla. Process the mixture until smooth. Be careful not to over-blend.
1 whole seedless navel orange, 4 eggs, 3/4 cup olive oil, 1 1/4 cup granulated sugar, 1/4 cup sour cream, 2 teaspoons vanilla extract
Add the dry ingredients to the blender. Pulse the blender just a few times until the dry ingredients are incorporated into the wet mixture. Do not overmix.
2 cups all-purpose flour, 3 teaspoons baking powder, 1/2 teaspoon sea salt
Pour the batter into the prepared loaf pan.
Bake the cake in the preheated oven for 50-55 minutes, or until a toothpick inserted into the center comes out clean and the top is golden brown.
Once baked, remove the cake from the oven and let it cool in the pan for about 10 minutes. Then, transfer it to a wire rack to cool completely.
Once the cake has cooled, you can serve it as is or dust it with powdered sugar for decoration.