Preheat oven to 325 degrees F. Butter and lightly flour a 12-cup bundt pan; chill in refrigerator. Set aside.
Using a box grater, grate the zucchini. Place the grated zucchini in a clean kitchen
towel (that you don't particularly care about), clump the ends, and squeeze out
the moisture into your kitchen sink. Squeeze several times to remove any
moisture. Place the grated zucchini in a bowl and set aside.
In a stand mixer bowl (fitted with a paddle attachment), combine the granulated
sugar and lemon zest. Using your fingers, rub the sugar and lemon zest together
until very fragrant. Add the softened butter, and beat mixture together at medium
speed 4 to 5 minutes or until flu!y. Add 1/4 cup lemon juice; beat until blended.
Add the eggs, one at a time, beating just until the yellow disappears.
Whisk together the flour, ground cardamom, salt, baking soda, and baking powder
in a medium bowl. Add the flour in three additions alternately with two additions
of ricotta cheese, beginning and ending with the flour mixture. Beat at low speed
just until blended after each addition. Fold in the grated zucchini.
Pour the batter into the prepared bundt cake pan. Bake 55 minutes to 1 hour or
until a long wooden pick inserted in center comes out clean. Cool cake in pan on a
wire rack 1 hour. Transfer cake to a plate, and cool completely (about 1 hour).
Whisk together the powdered sugar, lemon juice, and ground cardamom until
smooth. Drizzle glaze over cake.