Ensure your pumpkin puree is unsweetened and plain. Canned puree or homemade puree from roasted sugar pumpkins works best.
For a richer flavor, you can add a teaspoon of vanilla extract along with the spices.
This mousse can be made up to 2 days in advance. Keep covered in the refrigerator until ready to serve.
If you prefer a stronger ginger flavor, increase the fresh grated ginger to 1 teaspoon.