1. Remove the cream cheese, eggs (and yolks), and sour cream from the refrigerator and allow it to come to room temperature.

For the blueberry sauce

1. Dissolve the corn starch in the water and set aside.
2. If using fresh berries, wash and dry the berries. In a medium-sized saucepan, combine blueberries, sugar, and lemon juice; stir well.
3. Cook over medium-high heat, until the berries start to let out the juices and the mixture, starts to bubble, stirring often. Slowly add the cornstarch mixer 1 teaspoon at a time until the mixture starts to thicken (see notes). Turn down the heat and let simmer to allow the blueberries to further soften.
4. Cook until sauce thickens; around 10-15 minutes. Stir often so the bottom does not burn. Cool the sauce prior to adding to the cheesecake, refrigerate if necessary.

Make the crust

1. Preheat the oven to 325°F. Line a 9-inch springform pan with parchment paper in the bottom.
2. Grind the graham crackers into a fine crumb. Mix together with the brown sugar and then stir in the melted butter until well combined. Press the crumbs tightly into the bottom and up the sides of the springform pan
3. Bake at 325°F for 8-9 minutes. Allow the crust to cool. Then wrap the crust with a slow cooker liner and tie a knot in the side of the bag to secure around the pan. Set aside.

Make the filling

1. In a large mixing bowl, beat the cream cheese for 2 minutes until free of lumps then add the sugar and beat on low speed until completely smooth, scraping down the bowl occasionally.
2. Next add the sour cream, lemon juice, and vanilla extract and mix at low speed until well combined.
3. Whisk the eggs and egg yolks together and slowly add to the batter, ensure it’s well mixed before adding more. Scrape down the bowl occasionally.
4. Pour half the cheesecake batter into the prepared crust. Then add ¾ of the blueberry mixer and gently swirl with a knife. Top with remaining cheesecake batter and then blueberry sauce again. Gently tap the pan on the counter to remove any air bubbles on the surface or use a toothpick.
5.  Place the springform pan inside another larger pan. Fill the outside pan with approximately 2-3 cups of warm water so it is about halfway up the sides of the springform pan.
6. Bake at 325°F for approximately 60 minutes. The center should be set, but still slightly jiggly. Turn off the oven and leave the door cracked open for one hour. This allows the cheesecake to continue to cool slowly, which helps to prevent cracking.
7. Remove the cheesecake from the oven and water bath and cool for at least 2 hours on the countertop, then cover and move to the refrigerator. Refrigerate for 4-6 hours until the cheesecake has set. Add toppings prior to serving if desired.