Prepare the pie crust
Roll out one half of the dough and line a 9-inch pie dish. Trim excess edges and place in the fridge.

Mix the filling
In a large bowl, combine blueberries, blackberries, lemon juice, sugar, cinnamon, and cornstarch. Mix gently to coat the berries.

Add the filling
Pour the berry mixture into the chilled crust. Spread evenly.

Create Jack’s face
Roll out the second crust. Use a knife or printed stencil to cut out Jack Skellington’s eyes, nose, and stitched smile.

Top and seal
Carefully place the cut-out crust over the filled pie. Seal and crimp edges. Refrigerate for 15–20 minutes.

Brush and sugar
Beat the egg and brush it over the top crust. Sprinkle with coarse or turbinado sugar.

Bake the pie
Bake at 400°F (200°C) for 20 minutes. Reduce heat to 350°F (175°C) and bake for another 35–40 minutes, until the crust is golden and filling is bubbling.

Cool completely
Allow the pie to cool fully to set the filling before slicing.