In a small saucepan, combine maple syrup, blueberries, and lemon zest. Simmer over medium-low heat for 10-15 minutes, stirring frequently until the jam is thick. Spoon jam into a small jar. Cool for 30 minutes. Jam can be stored in a tightly sealed jar, refrigerated, for 2 weeks. Blueberries are naturally high in pectin, making this jam so simple to make and much healthier than the store bought alternative.