Preheat oven to 350 degrees F (175 degrees C). Grease a 12-cup muffin tin with ghee.
Separate the seeds from the stringy pumpkin guts. Place guts into a blender or food processor; pulse until pureed.
Mix brown sugar and butter together in a bowl until combined. Add pumpkin puree and eggs; whisk until well blended.
Sift 3 cups flour, baking powder, cinnamon, nutmeg, and salt together in a bowl. Add flour mixture to pumpkin mixture and stir until absorbed. Add as much of the remaining 1 cup flour as needed to create a batter that is moist but thick enough to stand a spoon in. Stir in chocolate chips.
Divide batter evenly between the 12 muffin cups.
Bake in the preheated oven until a toothpick poked into the center comes out clean, 20 to 25 minutes.