Yield: 12 muffins.

1 ¼ cups packed light brown sugar
½ cup canola oil
1 teaspoon vanilla extract
2 eggs
2 cups all-purpose flour
2 teaspoons baking powder
1 teaspoon ground cinnamon
1 teaspoon freshly grated nutmeg
½ teaspoon ground allspice
1 teaspoon salt
2 (15-ounce) cans sweet potato, drained
½ cup raisins (optional)
1 cup walnuts (optional)

Preheat oven to 350°. Grease muffin tins to hold 12 muffins.

Whisk together brown sugar, oil, vanilla, and eggs in a small bowl. Set aside.

Mix together the flour, baking powder, cinnamon, nutmeg, allspice, salt, and sweet potatoes in a large bowl. Make a well in the center, and pour in the egg mixture. Stir the egg mixture, gradually incorporating it with the flour mixture. Stir in the raisins and walnuts.

Spoon the batter into the tins and fill to the top. Bake the muffins for 25 to 30 minutes or until a toothpick inserted into the middle comes out clean. Remove the muffins from the oven and run a paring knife carefully around each muffin. Invert the pan to release the muffins. Serve right away.