Preheat your oven to 350. Grease with vegan butter or lightly oil an 8 or 9 inch round cake or cheesecake pan with a removable bottom. Line the bottom of the pan with a round piece of parchment.
To prepare the graham cracker crust: place the graham crackers and sugar into a food processor fitted with the S blade. Process for about 20 seconds, or until the crackers are turning into crumbs. Drizzle in the melted butter and continue processing for about a minute. The crust is ready when a small amount will stick together when you squeeze it in the palm of your hand.
Remove the blade from the processor and pour the crumbs into your prepared pan. Use the back of a measuring cup or a regular cup to smooth it out over the bottom and to the sides. You can use some pressure here! Pack the mixture down till it's smooth, solid, and even.
Transfer the baking pan to the oven and bake the graham cracker crust for 8-9 minutes, or until just starting to smell nutty. Remove the pan and set it and the pre-baked crust aside.
Clean and dry your food processor. Place the cashews into the food processor (fitted with the S blade). Alternately, use a high speed blender, such as a Vitamix. Add the three tablespoons of water. Cover the processor and pulse a few times. Run the processor for about 1 minute, until the cashews are broken down. Use a spatula to scrape the sides of the processor, then continue processing for another 2-3 minutes. The cashews should become relative smooth and blend without effort. Keep scraping the processor sides down if needed.
Add the lemon juice, cream cheese, sugar, vanilla, and cornstarch to the processor. Process for 3-4 minutes, or until you have a completely smooth mixture. You can stop and scrape down the side of the processor as needed. You'll have a smooth, thick mixture: pourable, but not runny, and it'll coat a spoon or spatula.
Transfer the cheesecake batter to your prepared, round baking pan. Transfer to the oven. Bake for 40 minutes.
Remove the cheesecake from the oven carefully. At this point, the center will still be very, very jiggly! It'll firm up during cooling. Allow the cheesecake to cool in a cool place for about 1 hour. Then, gently cover the top of the pan and transfer the cheesecake to your fridge. Chill the cheesecake overnight.
To make the blueberry sauce, place all ingredients in a saucepan over medium heat. When the mixture becomes bubbly, reduce the heat to low. Simmer, uncovered, for 10 minutes. Allow the sauce to cool before enjoying.
To serve, slice the cheesecake and top it as desired. Enjoy!
Leftover cheesecake can be stored in an airtight container in the fridge for up to 4 days. It can also be frozen for up to 6 weeks.