Preheat the oven to 350℉ and spray a 9-inch cake pan with cooking spray.
Add all the dry ingredients to a large bowl and whisk the ingredients together. Set aside.
Next, add the brown sugar and olive oil to a different mixing bowl and whisk together, making sure there are no lumps.
Add the remaining wet ingredients to the olive oil and brown sugar and whisk to combine.
Slowly add the dry ingredients to the wet ingredients and mix until smooth.
Transfer the batter to the cake pan. Set aside.
In a small bowl, add the granulated sugar and orange zest. Using your fingertips, rub the zest into the sugar. The sugar should become a light orange color. Top the cake with the orange zest sugar.
Bake for 35-45 minutes or until a toothpick inserted into the center comes out clean.
When the cake is done, remove it from the oven and allow it to cool before serving.