Preheat the oven to 400° F (200° C.) Line 12 muffin cups with muffin papers or spray with nonstick baking spray.
Mix the dry ingredients: in a large bowl, add the flour, brown sugar, baking powder, baking soda, salt, cinnamon, nutmeg, ginger, cloves, and allspice. Stir with a large spoon until fully combined, then make a well in the center.
Mix the wet ingredients: in a medium bowl, add the oil, eggs, vanilla, pumpkin puree, and milk. Whisk the wet ingredients until fully combined.
Pour the wet ingredients into the well you made in the center of the dry ingredients. Stir gently with a wooden spoon until the batter is fully combined, and there are no pockets of flour. Be careful not to overmix, or the muffins will be tough.
Distribute the batter evenly into the muffin cups and bake at 400° F (200° C) for about 16-18 minutes, or until the tops of the muffins spring back when touched. The muffins will keep well for a couple of days at room temperature, or for 4-5 days in the refrigerator. They will also freeze very well for 2 months.
