Preheat oven to 350° F.
Spray a standard muffin pan with cooking spray or line with paper baking liners if you wish. In a medium bowl, combine flour, sugar, salt, baking soda, baking powder, cinnamon, mace, nutmeg, and cloves. Make a well in the center of the flour mixture and set aside.
In another medium bowl, combine the eggs, pumpkin purée, and melted butter. Add the pumpkin mixture all at once to the flour mixture. Stir until just moistened (batter may be a bit lumpy). With a spatula, fold in the chocolate chips. Divide batter between the 12 prepared muffin cups. (I use an ice cream scoop for this.)
Spoon streusel topping on each muffin - enough to cover the top.
Bake for about 20-23 minutes, or just until a wooden toothpick inserted into centers of the muffins comes out clean. Do not over bake. Let muffin pan cool for 10 minutes before removing muffins to a cooling rack.