Preheat oven to 350°F (176°C).
Prepare the orange simple syrup by cooking the orange juice, sugar, and water on the stove for 10 minutes over medium heat. Stir occasionally.
Use a small sharp knife to cut away the skin and the pith from 2 oranges. Do your best to keep as much of the flesh of the orange in tact. Then, turn the orange on its side so the top of the orange is facing out to a side. Use the knife to make thin slices about 10-12 slices per orange.
In a large bowl combine the dry ingredients: flour, organic sugar, and baking powder.
Then, add in the wet ingredients: olive oil, non-dairy milk, vanilla extract, and juice from orange.
Mix all together to form a cake batter.
Spray a 9 inch cake pan. Then, line with parchment paper. Layer the sliced oranges all the way around the bottom of the pan. Make sure there are no holes around the base of the pan. You can also do 2 layers of the orange slices to ensure everything is covered well. Pour the simple syrup over the orange slices.
Pour the batter over the oranges and ensure everything is evenly dispersed.
Bake in the oven at 350°F for 50 minutes, or until golden and a toothpick comes out clean.
Allow the cake to cool in the pan for 20 minutes. Then, put a dish over the pan, and flip to reveal a beautiful upside down orange olive oil cake.
If desired, top with organic powdered sugar and garnish how you like