1. Preheat oven to 350 degrees.  Spray a 9 by 9 inch baking pan with nonstick spray.  Set aside.

For the Crust

1. In a bowl, mix graham cracker crumbs, melted butter, and sugar.  Pour into prepared pan and press firmly and evenly.  
2. Bake at 350 degrees for 10 minutes, and then allow the crust to cool while you make the rest of the cheesecake.  Turn the oven temperature down to 325 degrees.

For the Filling

1. In the bowl of an electric mixer with the whisk attachment, whisk cream cheese, sour cream, granulated sugar, and heavy cream on medium-low speed until smooth.  Add eggs and whisk again.
2. Add vanilla, lemon juice, and flour and whisk until incorporated. Scrape the bottom and sides of the bowl as needed with a rubber spatula and mix again.
3. Pour the cheesecake filling over the crust.  Set aside.

For the Topping

1. In a medium bowl, add butter, flour, and sugar.  Cut the butter into the flour with a pastry blender until you have small crumbles.
2. Place the fresh raspberries on top of the cheesecake filling, pressing down slightly so the raspberries are halfway submerged in the filling.  Sprinkle the streusel topping over the raspberries and filling.
3. Bake at 325 degrees for 40-45 minutes, then allow the cheesecake to cool at room temperature for 1 hour.  Refrigerate for six hours, or overnight to set fully.   Cut into squares and serve.