Pie crust for a 9'' deep dish pan. This recipe makes 2 crusts: one for the bottom and one for the top
7 cups fresh or frozen raspberries, blueberries and blackberries about 2 ⅓ cups of each
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
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 ¼ cup more
Spoon out about ½ 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.
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.