Grease the cups of two standard muffin tins or use paper liners. Set an oven rack to the middle position.

In a large bowl, stir together sugar, oil, eggs, pumpkin, and ½ cup water. In a medium-size bowl, whisk together flour, baking powder, baking soda, salt, and spices.

Add dry ingredients to wet ingredients and stir until moistened. Add raisins and walnuts and stir.

Let stand 20 minutes at room temperature. Preheat oven to 400°F.

Pour batter into prepared muffin cups, each two-thirds full. Bake until golden brown and domed, about 15
minutes.