Directions:

1 frozen pie crust

7 cups fresh or frozen raspberries, blueberries and blackberries about 2 1/3 cups of each type of berry*
▢ 1 cup granulated sugar (plus a little extra to sprinkle on top of the pie)
▢ 1 Tablespoon lemon juice
▢ 4 Tablespoons cornstarch
▢ 2 Tablespoons butter
▢ 1 large egg white beaten with a fork

Instructions

Cook berries: Add berries, sugar and lemon juice to a large saucepan over medium heat.

Simmer, until warm and juicy, about 5-10 minutes, gently stirring occasionally. (You can taste it at this point and see if it's sweet enough for your liking. I don't like to make mine too sweet, but if you want it sweeter you can add 1/4 cup more sugar.)

Thicken filling: Spoon out about 1/2 cup of the juice from the pan into a bowl. Stir cornstarch into the juice until smooth.
Bring pot of berries back to a simmer and slowly pour in the cornstarch. Gently stir mixture (being careful not to mash the berries), until thickened, about 2-5 minutes.

Cool and add to pie shell. Remove from heat and stir in the butter. Allow to cool for 15 minutes. Pour mixture into unbaked pie shell (in a 9 in deep dish pan).

Add lattice top or a whole top with holes pricked on top for steam to escape. (See directions for lattice crust below).

Pinch the edges of the top and bottom pie crusts together and crimp the edge, if you like. Brush a thin layer of beaten egg white over the top of the pie and sprinkle lightly with sugar.

Bake at 400 degrees F for 40-45 minutes. Check it after about 25 minutes and place a piece of tinfoil over it if the top crust is getting too brown.

Remove to a wire cooling rack and allow to cool for several hours. Once cooled completely, you can cut into it or cover it and refrigerate it overnight to serve the next day.