Preheat the oven to 350° degrees F.
Butter a 9 inch spring form cake pan, and arrange the candied orange slices at the bottom of the cake pan, set aside.
In a mixing bowl sift together the flour, baking powder, and salt.
In the bowl of a stand up mixer cream together the butter, sour cream, and orange zest.
Slowly add the sugar in two parts, mixing well between each addition and mix until it is light and fluffy.
Scraping down the sides of the bowl as needed.
Add the eggs, one at a time, mixing well.
Add the some of the sifted dry ingredients, mix well, then add some of the orange juice, and mix well. Alternate these two until everything has been added and mix well on low.
Pour the batter in the pan on top of the orange slices.
Bake 35 minutes and check with a toothpick. if the toothpick inserted in the middle comes out clean, remove the cake, or cook it for another 5-10 minutes.
Cool the cake in the pan for about 10 minutes.
pop open the spring form pan, and flip it onto the serving dish.
Allow to cool and serve cold, or serve warm. I tried it both ways and it was awesome!