1) Preheat the oven to 375°F. Line muffin tin(s) with papers, or grease each cup. Since this recipe makes 24 to 27 muffins, you'll use at least two tins; or simply bake as many as you want, and refrigerate the remaining batter, to use up to 4 days later.
2) Beat the sugar, oil, eggs, and vanilla till smooth and somewhat lightened in color, about 1 minute at high speed.
3) Add the baking powder, baking soda, salt, and cinnamon, beating to combine.
4) Add the flour, beating just till smooth.
5) Add the zucchini, nuts, and raisins or currants.
6) Divide batter evenly among the prepared muffin cups, filling them about 3/4 full.
7) Bake the muffins for 25 to 27 minutes, or until a cake tester inserted into a muffin comes out clean. Remove them from the oven, and after a minute or so gently tilt them in the pans, so their bottoms don't become soggy. As soon as you can handle the muffins, transfer them to a rack to cool.
Yield: 27 muffins.
Nutrition information per serving (1 muffin, 92 g): 335 cal, 17 g fat, 5 g protein, 19 g complex carbohydrates, 20 g sugar, 1 g dietary fiber, 61 mg cholesterol, 205 mg sodium, 142 mg potassium, 2 mg vitamin C, 1 mg iron, 66 mg calcium, 72 mg phosphorus.