Pre-heat oven at 400 degree Fahrenheit (or 200 degree centigrade). Line muffin tins with paper liners or spray oil on muffin tins.
In a bowl add egg, vegetable oil, pumpkin puree and sugar.
Whisk until smooth.
Add the flour, salt, baking powder, baking soda, pumpkin pie spice and vanilla extract.
Stir until just combined.
Fold 1 cup of semi-sweet or milk chocolate chips into the muffin batter. Don’t over work the mix. Mix until everything comes together.
Divide the batter evenly into muffin trays lined with muffin liners.
Sprinkle some extra chocolate chips on top.
Bake in pre-heated oven at 400 degree Fahrenheit (or 200 degree centigrade) for 12 to 15 minutes or until lightly golden browned and a tooth pick inserted in the middle comes out cleans.
Remove from oven. Let it cool for 5 minutes.
Remove from muffin tins and place it on wire rack to cool completely.
Or store them in air tight containers at room temperature for 5 days.