1. Preheat oven to 350°F, and grease a 9-inch springform pan. Whisk graham cracker crumbs, butter, salt and 1/4 cup of the sugar together in a medium bowl until combined. Press firmly onto bottom of the pan (or up the sides, if desired). Bake for 10 minutes, then remove and let cool. Reduce oven heat to 325 degrees F.
2. Once the pan reaches room temperature, carefully wrap the outside of the pan in 2 layers of heavy-duty aluminum foil, being sure that there are NO gaps where water could seep through. Place the pan in a large roasting dish (or any pan larger than the springform), and bring a tea kettle or pot of water to boil in preparation for the water bath. Set aside.
3. Using an electric mixer, beat cream cheese on medium speed for 3 minutes until smooth. Add the remaining 1 cup sugar and beat for an additional minute until well blended. Add Greek yogurt and vanilla, and beat for an additional minute, stopping partway to scrape the bottom of the bowl with a spatula. Add eggs, one at a time, beating on low speed after each addition just until blended. Do not overbeat! Pour into crust.
4. Place the double pans in the oven on a shelf on the bottom third of the oven. Very carefully use a tea kettle (or large measuring cup) to pour the boiling water in the larger pan to form a water bath around the springform, so that it comes up about 1-inch around the springform.
5. Close the oven door, and bake about 1 hour 30 min, or until center is almost set. (The cake should still jiggle ever so slightly.) Turn oven off, and open oven door slightly. Let cheesecake set in oven 1 hour. Then remove cheesecake from oven, carefully run a knife around the edges of the cake, and then let cool to room temperature. Refrigerate at least 4 hours or overnight. Remove springform rim, and top cheesecake with blueberry filling just before serving. Store leftover cheesecake in refrigerator in a covered container.

To Make The Blueberry Topping:

1. Bring blueberries and 1/4 cup water to a boil in a medium saucepan, stirring occasionally. In a separate bowl, whisk together 1 Tbsp. water and cornstarch until combined. Stir mixture into the blueberries, and boil for an additional minute until thickened.
2. Remove from heat and spoon over cheesecake just before serving.