In a small saucepan, combine 1 cup blueberries, sugar, ½ cup water, and lemon juice
Heat over low-medium heat to a low boil. In a small bowl, whisk the cornstarch and 2 tablespoons of water.
Slowly whisk cornstarch mixture into blueberries, being careful not to break blueberries. Cook for 3-5 minutes or until thick. The consistency of the blueberry sauce should look like so.
Cool completely. Store in an airtight container in the refrigerator.
Now, you are ready to make your delicious blueberry cheesecake!