Make pie crust according to my Perfect Pie Crust Tutorial. This recipe only requires one crust and the recipe makes two, so cut it in half if you are only make one pie.
Preheat oven to 375 degrees F
Place pie crust in bottom of 9 inch pie plate.
Par bake the pie crust for 5 minutes in the oven to help prevent it from getting soggy.
In a bowl, combine 1/2 C brown sugar, flour, cornstarch, lemon zest and lemon juice.
Add in blueberries and stir to coat.
Place blueberries in par baked crust.
In another bowl, combine 2/3 C brown sugar, oats, flour, cinnamon and butter.
Cut butter in until mixture is crumbly.
Spread crumb mixture onto of pie filling.
Bake for 30-40 minutes in preheated oven until top is browned.
Cool on a rack.
Notes
Fresh or Frozen Blueberries? I prefer to use fresh blueberries but you can use frozen. Use them frozen and realize the pie will need to cook several minutes longer.Tips:This is a great make ahead pie as it gives the juices plenty of time to cool down and thicken up. Make it the day before serving and let it sit overnight. You can also make the pie crust ahead of time and store in the refrigerator for 4-5 days or in the freezer for up to 3 months.After the pie is baked you can freeze it for up to 3 months. Before serving, thaw overnight in the refrigerator and bring to room temperature. The pie crust dough can also be prepared ahead of time and stored in the refrigerator for up to 5 days or in the freezer for up to 3 months.