Preheat oven to 350. Butter and flour 25 cm bundt pan. In a large bowl, whip butter until creamy. Blend in sugar, vanilla, eggs, and yolks. Beat until well blended. In a separate bowl, sift together flour, baking powder, and salt. Gradually add dry ingredients to butter mixture alternately with heavy cream and mix until smooth. Stir in orange juice. Add both grated lemon peel and juice. Pour mixture into prepared pan and bake 45 minutes or until cake tests done. Allow cake to cool in pan 10 minutes, then turn onto rack and remove pan and cool completely. Dust with confectioners' sugar and garnish with berries and mint leaves.