Preheat oven to 375 degrees. Whisk together the pumpkin, eggs, oil, buttermilk, molasses, ginger, cinnamon, and brown sugar in a mixing bowl. Sift together the flour, baking powder, baking soda, and kosher salt in a separate bowl.
Combine the wet and dry mixtures, stirring until just blended. Fill muffin cups about 2/3 full. Bake for approximately 8 minutes.