1. Preheat your oven to 375°F (190°C). If you’re using a homemade crust, roll it out on a lightly floured surface to fit your 9-inch pie dish.
2. Lay one pie crust into the dish, gently pressing it into the edges. Trim any excess dough hanging over the sides.
3. In a large bowl, combine the blueberries, chia seeds, sugar, cornstarch, lemon juice, lemon zest, cinnamon (if using), and salt. Stir gently to coat the berries evenly.
4. Pour the blueberry mixture into the prepared pie crust, spreading it out evenly.
5. Dot the filling with small pieces of butter. This little touch creates a rich, glossy finish once baked—Mama Lou’s trick that I swear by.
6. Cover with the second pie crust, trimming the edges to match the bottom crust. Pinch the edges together to seal. Cut a few small slits in the top crust to allow steam to escape.
7. If you like, whisk the egg and brush it over the top crust for a golden, shiny finish.
8. Place the pie on a baking sheet (to catch any drips) and bake for 45-50 minutes. The crust should be golden brown and the filling bubbling through the vents.
9. Remove from the oven and let cool completely on a wire rack. This cooling step is key to allowing the chia seeds to thicken the filling properly.

One thing I’ve learned from years of baking with Mama Lou is patience. Rushing the cooling phase can leave your pie runny, and there’s nothing worse than slicing into a beautiful pie that falls apart. Trust me, it’s worth the wait!