Pre-heat oven to 350 degrees. Line a baking sheet with SILPAT and set aside.
In a medium bowl, mix all dry ingredients except M&Ms and set aside.
Line a small bowl with paper towels, then add pumpkin on top. Blot the pumpkin dry with another paper towel. Continue blotting dry until pumpkin no longer quickly soaks through the paper towel with moisture.
Add all wet ingredients to dry mixture and stir until combined. Fold in M&Ms, then scoop cookie dough onto lined baking sheet using a 1 1/2 tbsp scoop (the dough will be sticky, so it's best to use a cookie scoop for this step).
Flatten cookie dough scoops slightly before baking - they will spread slightly on their own but need a bit of help. If desired, press a few additional M&Ms into the tops of the cookies before baking.
Bake cookies at 350 degrees for 13-15 minutes. They will be slightly soft to the touch when they come out of the oven. Allow them to cool for at least 10 minutes before removing from the baking sheet.