1 1/4 to 1 1/2 pounds zucchini, unpeeled, finely grated
1 cup all-purpose flour
1 1/2 teaspoons baking powder
2 teaspoons sugar
2 teaspoons plus a pinch of kosher (coarse) salt
2 large eggs, separated
1/3 cup milk, preferably whole milk
1 tablespoon butter or margarine, melted
Vegetable oil or solid vegetable shortening, for deep-frying
1/3 cup freshly grated Parmesan cheese
Spread the grated zucchini on ink-free paper towels to drain.
Stir the flour, baking powder, sugar, and the 2 teaspoons salt together in a large bowl.
Beat the egg yolks well in a separate bowl. Stir in the milk and melted butter.
Beat the egg whites with an electric mixer on medium-high speed until foamy. Add the pinch of salt, increase the speed to high, and beat until stiff peaks form.
Stir the egg yolk mixture and the drained zucchini into the flour mixture. Carefully fold in the beaten egg whites.
Pour oil to a depth of 1 to 2 inches in a deep-fryer or a large, deep frying pan. Heat the oil to about 375°F.
Carefully drop the batter, 1 tablespoon at a time, into the hot oil. (Do not crowd the pan, or the temperature of the oil will decrease and the fritters will be soggy.)
Fry, turning once, until golden brown all over, about 3 minutes. As they are cooked, use a slotted spoon to transfer the fritters to ink-free paper towels to drain. Continue frying until all the batter is used.
To serve, shake the fritters in a paper bag with the Parmesan cheese. Serve hot.