Preheat the oven to 400 degrees and line a baking sheet with parchment paper.
Add the berries, sugar, vanilla, cinnamon, and salt to a mixing bowl, and mix well. Place the pie crust on the parchment lined baking sheet, and brush with jam (optional).
Place the pie crust on the parchment lined baking sheet, and brush with jam (optional).
Pour the fruit onto the center of the pie crust, leaving a 2-inch border around the edges.
Fold the crust over in 2” sections, making overlapping folds as you go.
Brush the pie crust with the egg whites.
Bake for 25-30 minutes, until golden brown.