Sour cherries are a time-honored choice for pies -- they lend a lovely tartness that their sweet cousins Bing and Rainier cherries just can't offer.
Preheat oven to 375 degrees, with racks in middle and lower thirds. In a large bowl, stir together 1 tablespoon flour, granulated sugar, and 1/4 teaspoon salt. Stir in cherries and vanilla. Brush crust with egg white and fill with cherry mixture.
In a food processor, pulse together remaining 1 cup flour and 1/4 teaspoon salt. Add brown sugar, butter, and almonds; pulse until large pieces form. Scatter crumble over cherry filling.
Bake on middle rack, with a foil-lined rimmed baking sheet on lower rack to catch drips, until topping and crust are golden, 45 minutes. Tent pie loosely with foil; bake until juices in center are bubbling, 30 to 45 minutes more. Transfer to a rack and let cool. Serve warm or at room temperature. Cover and keep at room temperature, up to 3 days.
At the store, look for deep-dish crusts. Roll dough 1/8 inch thick and crimp as desired.