Set out the cream cheese and eggs at room temperature for an hour before using them.
To make the crust, crush the graham crackers, if needed, by placing seven cracker sheets at a time in a sealed plastic bag. Crush them with a rolling pin.
Add the crumbs to a small mixing bowl. Melt the butter in the microwave or a pan on the stove and add the melted butter to the crumbs. Stir in 3 tablespoons of sugar. Stir the crust mixture until it's blended well, and all the crumbs are moist.
Lightly grease a 9x13 pan with cooking spray. Transfer the crust mixture to the pan and press it evenly onto the bottom surface, not the sides. Set the crust aside to be baked later with the cheesecake filling.
Preheat your oven to 325 degrees F. To make the cheesecake filling, add the softened cream cheese to a large mixing bowl or stand mixer. Beat the cream cheese until it's thick and creamy, getting rid of any lumps as best you can.
Add the room-temperature eggs and 1 ½ cups of sugar. Beat until blended and no lumps remain, scraping the bottom of the bowl as needed.
Add the flour and vanilla. Beat to blend.
Add the half & half and beat at a low speed (to avoid splashing). When the mixture is blended, beat it some more until you see some bubbles on the surface.
Pour the batter over the unbaked graham cracker crust. Bake the cheesecake for 45-50 minutes, or until it's set. Some ovens may take longer.
Let the cheesecake cool on a wire rack. Wait at least 30 minutes before adding the sour cream topping.
To make the topping, add sour cream to a small mixing bowl. Stir or mix in ¼ cup of sugar. When the cheesecake is cooled off, spread on your sour cream topping.
Cover the pan with foil (be careful not to let the foil touch the cheesecake surface) and refrigerate the cheesecake overnight. Serve the cheesecake chilled, with fresh blueberries, if desired.
Store the cheesecake covered in the refrigerator for up to three days. If you want to make this ahead of time to freeze, don't freeze the topping. Just make the plain cheesecake and freeze it. Thaw it overnight in the refrigerator, then add the sour cream topping before serving.
This cheesecake needs to be made at least a day in advance but tastes even better 2-3 days after you make it, as the crust softens.