Position rack in center of oven and preheat to 350°F. Line 9-inch-diameter cake pan with 2-inch-high sides with parchment paper. Coat parchment paper with nonstick spray.
Whisk flour, baking powder, coarse salt, cinnamon, ginger, and nutmeg in medium bowl to blend well. Whisk oil, sugar, eggs, and vanilla in large bowl to blend well; fold in flour mixture, then grated zucchini and pecans. Transfer cake batter to prepared pan.
Bake cake until tester inserted into center comes out clean, about 45 minutes. Cool cake completely in pan on rack, about 1 hour. Cut around sides of pan to loosen. Turn cake out onto platter; peel off parchment paper.
For frosting: Using electric mixer, beat cream cheese and butter in medium bowl until blended. Beat in sugar, vanilla, and cinnamon. Spread frosting thickly over top of cake.
Adapted from Bon Appétit, August 2010, by Ian Knauer