Preheat oven to 375 degrees Fahrenheit. Place crust in a 9 inch deep dish pie plate. Flute edges and prick bottom of the crust in several places with a fork. Set aside
In a small mixing bowl, with a fork, combine the butter, brown sugar, ¼ cup of the all purpose flour, and the pecans until crumbly. Set aside.
In a large mixing bowl with a hand mixer on medium speed; beat the granulated sugar, eggs, and cream cheese together till smooth. Reduce the speed to low and beat in the remaining 2 tablespoons of flour and the sour cream. Grate the zest from the lemon in the bowl and squeeze the juice from the lemon in the bowl. Stir with a spoon till mixed. Gently fold in the blueberries. Pour into the prepared crust and bake on bottom rack of oven for 15 minutes with edges of crust covered with foil or a pie crust shield to prevent excessive browning.
Remove from oven and sprinkle with nut mixture. Remove pie shield and return to oven on top rack and cook 12 to 15 minutes more or until crust is light golden. Cool completely. Serves 8 to 10. Refrigerate leftovers.