Preheat the Oven

Preheat your oven to 375°F (190°C). This ensures the crust starts baking immediately and becomes golden and crisp.

Prepare the Filling

In a large mixing bowl, combine the marionberries, sugar, cornstarch, lemon juice, lemon zest, salt, and vanilla extract.

Gently stir until the berries are evenly coated.

Prepare the Pie Crust

Place the bottom pie crust into a 9-inch pie dish. Press it gently into the edges and trim any excess dough.

Add the Filling

Pour the berry mixture into the prepared crust. Spread it evenly so the filling cooks uniformly.

Add Butter

Dot the top of the berry filling with small pieces of butter. This adds richness and flavor to the pie.

Add the Top Crust

Cover the pie with the second crust.

Seal the edges by crimping with a fork or your fingers. Cut small slits on top so steam can escape during baking.

Egg Wash (Optional)

Whisk the egg and milk, brush it over the top crust, and sprinkle with coarse sugar for a golden, slightly crunchy finish.

Bake the Pie

Place the pie on the middle rack and bake for 45–50 minutes, until the crust is golden brown and the filling is bubbling.

Cool Before Serving

Let the pie cool for at least 2 hours so the filling sets properly. Cutting too soon can make it runny.