Preheat oven to 325 degrees.

Brush a 6-cup bundt pan with butter, and dust with flour, tapping out excess (or do the same with two loaf pans). Whisk together flour, baking powder, spices and salt.

Grate zucchini on the large holes of a box grater, or in your food processor, then squeeze dry in a clean kitchen towel. (You need about 2 1/2 cups.)

Stir together eggs and sugar, then stir in melted butter, zucchini, and 1/2 teaspoon orange zest and juice. Stir in flour mixture. Transfer batter to pan.

Bake until a toothpick inserted into the center comes out clean, about 1 hour (cake will rise quite a bit but should not run over). Transfer pan to a wire rack, and let cake cool for 10 minutes. Run a knife around edges of cake to loosen, and turn out onto wire rack. Let cool for at least 30 minutes.

To make the frosting, beat cream cheese and butter in medium bowl with an electric mixer. Beat in sugar, vanilla, remaining 1/2 teaspoon orange zest, cardamom and salt. Chill.

Frost cake generously with cream cheese frosting.

*Unglazed cake can be stored at room temperature, wrapped in plastic wrap, for up to 1 day, or frozen for up to 1 month.