Place cashews in a bowl. Cover with water and let soak overnight. Alternately, use the quick-soak method by boiling the water first. Soaking time will be reduced to 20-30 minutes.
Strain and rinse cashews. Discard soaking water. Add soaked cashews to the pitcher of a blender (preferably high-speed like Vitamix). Add 1 1/2 cups water, 2 tablespoons maple syrup, pumpkin puree, pumpkin pie spice mix, and salt. Puree until completely smooth, about 1 minute on high.
Taste and add more pure maple syrup if desired. I don't like super sweet coffee creamer, and I find that about 3 tablespoons total is my sweet spot. No pun intended.
The following step is completely optional, but if you'd like an extra smooth creamer, you can strain it through a nut milk bag or a fine-mesh sieve lined with cheesecloth (the nut milk bag is much easier). But I usually skip this step.
Use the creamer right away, or pour it into an airtight container and refrigerate until ready to use. I stir about 2-3 tablespoons into each cup of coffee. Keeps for about 5 days. It may separate a bit in the fridge; simply give it a shake before using.