Boil clementines for two hours, covered. Drain and cool. If your clementines have seeds, remove them. Vigorously mix the clementines together to until you have a thick paste.

Preheat oven to 375 degrees. Grease a 9-inch pan, and place a round piece of parchment paper on the bottom. Line the perimeter of the pan with thinly-sliced, fresh clementines. 

Mix the clementine paste, sugar, and brown sugar together until smooth. Add the rest of the ingredients, and mix until uniform. Pour into the prepared pan and place in the oven on the middle rack. 

Bake for about 40-50 minutes. Every time I’ve made this cake, the baking time varies. Be sure to start checking for doneness at 40 minutes or earlier. If it looks like it’s burning, cover with foil for the last few minutes. When I baked it in a cast iron skillet it only took 30 minutes. It’s done when it no longer has a jiggle in the center and is firm to the touch. 

Cool in the pan for about 30 minutes. Remove from the pan by loosening the sides with a butter knife, placing a serving dish over the cake pan, and flipping the cake upside down onto the serving dish. Remove the parchment paper.

Sprinkle with powdered sugar and shaved chocolate.