When making your coffee as usual, add a teaspoon of cinnamon to the grounds in the brew basket. Voila! It's really that easy!
After trying that one, I experimented a little this weekend with the following ...
Pumpkin Spice Coffee:
Make your coffee as usual, add a 1/2 teaspoon of cinnamon and 1/2 teaspoon of allspice.
Make your coffee as usual, add a 1/2 teaspoon of allspice and a 1/2 teaspoon of ginger.