Preheat oven to 350. Grease and flour a 6-cup bundt,k tube or fluted cale pan.
In a medium bowl, mix together the grated carrot, ginger and cinnamon and set aside.
In another bowl, whisk the flour, baking powder and salt together and set aside.
In a large bowl, at medium speed, beat together the butter, sugar and vanilla well until light and fluffy. Add the eggs, one at a time,beating well after each addition. (Don't worry if the batter appears curdled.).
At low speed, gradually beat in the flour mixture until the batter is smooth.
Fold half the batter into the carrot mixture, then fold in the chopped nuts if using. Set aside.
Fold the drained crushed pineapple into the remaining batter.
Spread the pineapple batter in the prepared pan, then spread the carrot batter on top. Using a knife, swirl gently through the batter to create a marble effect.
Bake for about 35 to 40 minutes or until top is golden and a toothpick inserted in the center comes out clean.
Transfer the pan to a rack to cool for about 10 to 15 minutes, then invert cake to the rack, remove the pan, and let cool completely.