Put the pumpkin pie spice in a small saucepan and let them toast on medium heat for 1 minute. Don't leave them unattended, and remove them from heat immediately if they start to burn.
After 1 minute, add the pumpkin puree and brown sugar. Whisk the ingredients together until they are well-mixed—heat for about 30 seconds.
After 30 seconds, remove from heat and add the milk and cream. You can substitute the heavy cream for half-and-half if you want to make a low-fat creamer. Whisk vigorously until the mixture has a smooth texture.
Pour the mixture into a heat-proof container. We prefer to use glass since it's easy to clean and won't hold any flavors or scents.
Let the mixture sit until room temperature, cover with a lid, and put it in the refrigerator.
This makes enough creamer for about 5-6 coffee drinks and will keep for up to 5 days.