Grease and flour 2 bread pans. Preheat oven to 350 degrees F.
In a large bowl mix the butter, shortening, and sugar until well blended with a electric mixer. Add the eggs and vanilla and blend in.
Sift together the flour, salt, baking powder, baking soda, cinnamon, and cardamom and add to the cream mixture and mix until well blended. Add the grated zucchini and mix in with a spatula.
Divide the batter between the 2 pans and place in the preheated oven.
Bake for about 45 minutes or when a wooden pick is inserted it comes out clean. Cool for a few minutes and remove from pan. Set on cooling rack and cool completely.