What you seem to be describing is a carrot cake baked in a tube pan. Frost the cake and put the rest of the frosting in the middle. As for what to dip, serve with preztel sticks or gingerbread cookies. Fruit doesn't dip well in frosting that has set.
If you chill the leftover frosting, you can use a mellon baller and make balls and roll them in crushed nuts and serve on decorative toothpicks. Place your pretties around the outside of the cake.
I have halved my frosting and colored one pink and the other blue for a baby shower and put them on top of frosted cupcakes with sprinkles.
"I have not failed. I've just found 10,000 ways that won't work." --- Thomas Edison