How to Make It
Bring 1 cup blueberries, sugar, water, lemon juice, and lemon zest to a boil in a small saucepan over medium-high heat. Reduce heat to low, and simmer, stirring occasionally, 8 to 10 minutes or until mixture has thickened and berries begin to break down. Remove from heat, and stir in remaining 1 cup blueberries. Cool completely (about 1 hour); cover and chill until ready to use.