Preheat the oven to 350 degrees. Grease 12 muffin cups.
In a small bowl, stir together the flour, baking powder, baking soda, cinnamon, salt, and ginger. Set aside.
Crack the egg into a small bowl. Then in a large bowl, use a fork to stir together the sugar and oil until blended. Stir in the egg, pumpkin, and yogurt until blended.
Stir in the flour mixture just until blended.
Gently stir in the oatmeal and the raisins (if using) just until incorporated.
Use a 1/4 cup measure to scoop the batter into the mffin cups. (be sure to check that the muffin cups are 2/3 full)
Bake the muffins until a toothpick in the center comes out clean, about 25 minutes. Turn the muffins out onto a rack to ool slightly. Serve mufffins warm or at room temperature. Store in a covered container for up to 3 days.