Preheat the oven to 350°. Grease or line a 12-cup standard muffin tin with paper liners.
In a bowl, combine the flour, baking soda, cinnamon, pumpkin pie spice, and salt. Set aside.
In a large bowl combine the butter and sugars. Mix with an electric mixer until light and fluffy, about 2 minutes. Add in the eggs one a time and mix until combined. Mix in the pumpkin puree and vanilla.
Pour the dry ingredients into the wet ingredients and mix everything together gently until just combined and no flour is left in the batter. Add the chocolate chips- save a handful of chocolate chips to add to the tops of the muffins right before you bake them.
Pour the batter into the muffin tins (fill ¾ of the way full).
Bake for about 18-22 minutes, until the muffins are set and a toothpick inserted into the center one comes out with just a few moist crumbs.
Let the muffins cool 10 minutes before removing from the pan. If you greased the pan, run a thin knife around each muffin to loosen it from the pan first. Serve warm or at room temperature.
Notes
Leftover muffins can be kept in an airtight container at room temperature for up to 5 days, or frozen for up to 3 months.
spoon and level your flour- I always recommend spooning and leveling your flour when baking. Scooping the measuring cup right into the flour will actually compact the flour and give much more than the recipe calls for. To spoon and level, use a large spoon to gently scoop the flour into your measuring cup. Once it's full, use a flat edge (like a butter knife) to gently scrape across the top of the measuring cup.
Don't overmix the batter- when mixing the dry and wet ingredients, only mix until you no longer see the streaks of flour. Overmixing the batter can lead to dense muffins that aren't fluffy.
Only fill the liners ¾ of the way- to avoid overfilling and spilling when they bake, only fill the muffin cups ¾ of the way full.
Check your muffins in the oven- all ovens bake differently, so make sure to check them around 15 minutes to see if they are baking too fast.