Preheat the oven to 375°F. Line a baking sheet with parchment paper. Mix together all the ingredients for the crust. It will be sticky. Spray the parchment with a cooking spray like coconut oil.
Press the mixture into a rectangular shape an inch thick. Place the crust in the oven and par-bake until it starts to turn golden brown on top, about 20 minutes.
Remove from the oven when done and set aside. While the crust is cooking, toss the blueberries, arrowroot starch, maple syrup, and lemon zest and set aside.
In a separate bowl, mix all the ingredients for the streusel topping together. Reduce the oven temperature to 350°F. Top the par-baked crust with the blueberry filling and top with the streusel. Bake for another 20 minutes or until streusel is golden in color and blueberries have started to pop. Let cool completely (at least an hour) before cutting into bars. Enjoy all week, just store these goodies in the fridge.