1 round refrigerated pie dough (half of a 14-ounce package)
1/4 cup sliced blanched almonds
6 McIntosh or Braeburn apples, peeled and chopped
11 tablespoons sugar
4 tablespoons unsalted butter
2 tablespoons fresh lemon juice
2 teaspoons pure vanilla extract
3 large egg whites, at room temperature
Pinch of salt