Place clementines in a small sauce pan with water and bring to a boil. Cover and simmer for 90 minutes. Remove boiled oranges from pot and let them rest for about 20 minutes or until they are cool enough to handle. Cut into quarters and remove any pits. Purée in food processor until smooth.
Preheat oven to 350. Grease and line with parchment paper 9 inch round pan.
Add olive oil, sugar, brandy and eggs to the oranges and process for about a minute. Add remaining ingredients and pulse until all of the dry ingredients are incorporated. Pour batter into prepared pan. Add the wrapped coin and bake on middle rack for 30 -35 minutes. Let cake cool then dust with powdered sugar.
For citrus garnish. Place slices of orange on a parchment lined baking sheet and "roast" for 15 minutes at 425 degrees. Cover cake with plastic wrap