In saucepan, combine blueberries, vinegar, water, and maple syrup and bring to boil over high heat. Reduce heat and simmer for 5 minutes on medium-high heat. Remove pan from heat, season with pepper and salt, and set pan aside to cool for 10 minutes.

In blender or food processor, blend mixture and then pass through a sieve. (Collect solids from the sieve and spread them on toast.) Place sauce in jar and keep in the refrigerator for up to 1 week. It’s equally delicious served cold or gently warmed.