5 ½cups(780g)fresh or frozen triple berry blend (raspberries, blackberries, blueberries)
1cup(212g)granulated sugar
4tablespoons(37g)cornstarch (see note!)
1tablespoonlemon juice
Pinch of salt
1largeegg, for egg wash (optional)
Instructions
Preheat oven to 375 degrees F.
Roll out bottom pie crust and place in pie pan, easing the pie crust into the edges of the pie plate without stretching. Trim edge, leaving a 1/2-inch overhang.
In a large bowl, add the berries. If frozen, let them sit at room temperature for 5-10 minutes so they begin to thaw just slightly (this helps to better combine the sugar and cornstarch with the berries so it thickens properly while baking).
Add the sugar, cornstarch, lemon juice and salt to the berries and stir gently (so the berries don't get crushed) until the berries are evenly coated and there aren't any pockets of dry, loose ingredients.
Scrape the filling into the pie plate and spread evenly.
Roll out the top crust and cut into strips for the lattice top. Lay strips vertically across the pie, leaving space in between. Fold up every other strip and place another pie crust strip perpendicular. Fold down the strips. Lift up all the strips underneath the perpendicular strip and place another strip perpendicular. Fold down the strips. Repeat that pattern until the lattice top is complete (see pictures in the post).
Trim the strips even with the bottom pie crust. Fold and press the bottom crust over the top of the strips around the edge of the pie. Flute the edge.
Place the pie on a foil-lined baking sheet and bake for 75-90 minutes until the pie is bubbling throughout. Check the pie around 60-65 minutes and tent the top very loosely with foil if it is browning too quickly. It's very important to cook the pie long enough or the filling won't thicken properly. The bubbles of filling you can see under the lattice crust should be thick and syrupy, not thin and runny.
Remove the pie from the oven and let cool for at least 2-3 hours. To ensure the most set up filling, let the pie cool completely. (Slices of pie can be reheated for just a few seconds in the microwave.)
Notes
Pie Crust Recipe: I alternate between this flaky pie crust and this sour cream pie crust. Both are fantastic recipes and can be used in this recipe (or use your favorite homemade recipe or store bought pie crusts). Cornstarch: I prefer using 4 tablespoons (1/4 cup) cornstarch for this recipe. If the pie cools completely, the filling sets up perfectly. If you are planning to serve the pie slightly warm, use 5 tablespoons cornstarch, but make sure to cook the pie for long enough! If not, the pie filling will have a starchy, uncooked taste and the filling will still be runny. Tapioca flour (1/3 cup) can be subbed for the cornstarch. Runny Filling: if your pie filling is runny when serving the pie, it's very likely due to needing more time to bake, more time to cool, or a bit more cornstarch in the filling.