Pour half the blueberries (1 cup) into a medium sauce pan and set aside the remaining 1 cup. Add the water, honey and cinnamon and cook over medium-high heat. Once boiling, reduce to a simmer and cook for an additional 10 minutes.
After 10 minutes, gently smash the blueberries against the pan using a wooden or plastic spatula. Add the remaining blueberries and cook for an additional 5-6 minutes to heat through.
Add lemon juice, if desired, to taste. (This will make the blueberry flavor pop a little bit more but isn't necessary.)