1. For the candied orange slices: If any of your oranges for candying have a skin thicker than about ¼ inch, remove the skin and most of the pith before adding to the syrup. Combine honey and water in a medium skillet and bring to boil. As soon as it begins to boil, add the citrus wheels, making sure they are mostly covered in the syrup. Reduce the heat to a simmer and cook for 15 minutes. Using tongs, gently move the slices around occasionally to ensure they are evenly cooked. Turn off the heat and allow them to cool while you prepare the cake. 

2. For the cake: Preheat the oven to 350° F. Generously grease a 9-inch springform or round cake pan. Line the bottom with a piece or parchment cut to fit the pan and grease the parchment. In a large bowl or the bowl of a stand mixer, use your fingers to thoroughly mix the orange zest into the sugar.

3. Whisk the dry ingredients together in a separate bowl. 

4. Add the butter to the sugar and cream together until lighter in color (with either a stand mixer or a handheld mixer). It is okay if the sugar is not fully dissolved. Add eggs one at a time and incorporate them well. Add the vanilla and yogurt and mix again before adding the dry ingredients. Mix until you have a smooth batter, stopping to scrape down the sides as necessary. 

5. Use tongs to gently lift each orange slice from skillet, allowing the excess syrup to drip into the skillet before arranging them in an overlapping pattern in the bottom of the prepared baking pan. Do not discard the syrup. Pour the batter over the oranges and carefully smooth the top so as not to disturb the orange slices. Bake for 35 minutes, or until the top is lightly browned and a toothpick inserted into the center comes out clean. 

6. While the cake bakes, gently boil the leftover syrup over medium heat until reduced by half, about 10 minutes. 

7. Once the cake is done, remove the pan from the oven. If you’d like a sweeter cake, prick the cake all over with a fork and pour the reserved syrup evenly over the cake. Otherwise, store the leftover syrup in the refrigerator for another use (it’s great in sparkling water, cocktails or mocktails, and drizzled over yogurt). Allow the cake to cool for about 15 minutes before covering with a plate and carefully flipping the pan over so the cake falls orange-side up onto the plate. Remove the parchment. Allow the cake to cool completely. Slice and serve with fresh whipped cream or a dollop of yogurt if desired.