Add 1 box of the Nature ValleyTM granola bars in a food processor and process until you achieve a fine crumb. Put the crumbs in a bowl. Do the same with the second box of granola bars and put them in a separate bowl.
In a large bowl, add the crumbs, brown sugar, flour and melted butter and mix together. Then spread into an 8×8-inch dish that has been covered with parchment paper.
Bake at 350oF for 10 minutes. Let cool.
In a mixing bowl, combine eggs whites and sugar and mix on high. Add the heavy cream and continue mixing for another 5 minutes.
In another bowl, mix squeezed lemon juice and softened cream cheese. Mix on low speed until incorporated. Add to the heavy cream mixture and continue to beat on high.
Add in the vanilla, cinnamon and fold in the blueberries. Pour the whipped mixture over the already baked crust.
Add two tablespoons of melted butter to the second bowl of crumbs to moisten it. Then crumble over the top.
Cover and freeze for three hours or more and enjoy!