To make the blueberry jam, combine the blueberries and sugar in a small saucepan. Cook over medium heat until the blueberries release their juices and the sugar melts.
Mash the blueberries, reduce the heat to low, and simmer for 15 minutes, stirring occasionally.
Allow the jam to cool, then stir in the lemon juice and a bit of lemon zest. Transfer it to an airtight container and refrigerate overnight.
While the blueberries are simmering, prepare the overnight oats by adding all the ingredients to a storage container or jar.
Stir well to combine, then fold in a handful of fresh blueberries. Cover and refrigerate overnight, or for at least 5-6 hours.
The next day, layer the cheesecake overnight oats just before serving. Start with a layer of granola, then add some of the overnight oats, a dollop of vegan Greek yogurt, some blueberry jam, and finish with a sprinkle of granola and fresh blueberries. This recipe makes 2 breakfast sized servings or 3-4 smaller snack sized servings.