Dissolve sugar in water, add spices and pumpkin puree. Let it boil, but not bubbly. Let it simmer for 10 minutes. Pass through a strainer or a clean tea towel.
Add one to two tablespoons per cup of coffee, depending on your taste.
It is best to use a ripe aromatic pumpkin. If you want, you can also make your own gingerbread spice. I think it tastes even better then.