Whisk together flour, sugar, cocoa, baking powder, salt, and baking soda. In
another bowl, stir together butter, eggs, vanilla, and zucchini. Stir into dry mixture,
then fold in chocolate. Pour into pan, smoothing top with a spatula. Bake until a
skewer inserted into the center comes out clean, about 1 hour 20 minutes. Let
cool 20 ...