If your from the south or have eaten southern cooking,then then you know what I mean when I say it is Blackberry picking time. LOL. You eat more then you pick and when you mix that with walnuts and cream cheese there is no going back!
Preheat the oven to 350 degrees F. Grease 9x13 baking pan. Crush vanilla wafers. Place cookies into gallon size plastic zip lock bag and use a rolling pin to roll over and over until all are crushed fine. Chop nuts finely, if using in a nut grinder.
If you don't have a nut grinder,you can place in a ziplock and use a meat tenderizer to break into pieces. In a medium size bowl mix together cookie crumbs,ground nuts and butter. Cream together well. Mix in vanilla. Press into prepared baking pan for the crust.
In a medium size bowl cream together cream cheese and powdered sugar. Whip eggs and add to cream cheese mixture, blend in well. Mix in sour cream. Smooth the filling over crust in baking pan. Bake for about 50 minutes or so. Remove from oven.
Cover lightly with foil for about 15 minutes. Remove cover and let cool. In a saucepan over medium heat,add enough water to just cover bottom of pan. Mix in blackberries and sugar. Bring just to a boil stirring frequently for about 5 minutes.
In small bowl add flour and 2 Tbsp water together. Add to Berry mixture,bring to a boil for about 1-2 minutes or until desired
thickness. Remove from heat. Let cool. Pour blackberry sauce over cheesecake. Let chill in frig over. Next day cut into 15 squares and serve.