Preheat oven to 350 degrees F. Spray (9-inch bundt pan) with cooking spray. You can also put this in a 8 x 4 1/2-inch loaf pan. Or a 8 or 9-inch cake pan. Basically, you got options!
In a medium bowl, whisk together the flour, baking soda, salt, and cinnamon. In another medium bowl, beat together the eggs, sugar, oil, buttermilk and vanilla until smooth. In two batches, add the flour mixture, mixing just until the flecks of flour disappear. Don’t be shy to scrape the bottom of the bowl to make sure there aren’t any flour bits hiding. Fold in the grated carrot, pineapple, coconut and pecans. Pour the batter into the prepared bundt or cake pan or whatever pan you’re using.
Transfer to the oven to bake for 20 to 25 minutes or until a wooden pick inserted in the center comes out clean. Allow the cake to cool in the pan for 10 minutes (the edges should start to come away from the pan). Turn the cake onto a cake stand or plate.
Meanwhile, in a bowl of a stand-up mixer (or you could use a hand-mixer), add the butter, cream cheese, powdered sugar and a tablespoon of buttermilk. Beat until very smooth. Add 2 more tablespoons of buttermilk. The texture should be between a glaze and a frosting. If you like, you can add a bit more buttermilk to make it more pourable. I liked it like this! Pour the frosting glaze stuff onto the cake. Slice it up and serve at your convenience.