Instructions

for the filling

 Combine cherries and ¼ cup sugar in large bowl and let sit until cherries are softened and juices have been released, about 2 hours. Transfer cherries and any accumulated juices to fine-mesh strainer set over 8-cup measuring cup or large bowl. Press fruit with rubber spatula to release 1 cup juice; reserve juice and fruit separately.

for the crust

 Meanwhile, combine ice water and sour cream in bowl. Process flour, sugar, and salt in food processor until combined, about 5 seconds. Scatter butter over top and pulse until butter pieces are no larger than peas, about 10 pulses. Drizzle ice water mixture over top and pulse until dough forms clumps and no dry flour remains, about 12 pulses, scraping down sides of bowl as needed.
Transfer dough to counter and knead briefly until dough comes together. Form dough into 5-inch disk, pressing any cracked edges back together. Wrap dough in plastic wrap and refrigerate for 1 hour. (Wrapped dough can be refrigerated for up to 2 days or frozen for up to 1 month. If frozen, let dough thaw completely on counter before rolling.)
Let chilled dough sit on counter to soften slightly before rolling, about 10 minutes. Roll dough into 12-inch circle on lightly floured counter. Loosely roll dough around rolling pin and gently unroll onto 9-inch pie plate, letting excess dough hang over edge. Ease dough into plate by gently lifting edge of dough with your hand while evenly pressing dough into plate bottom and corners with your other hand.
Trim overhanging dough to ½ inch beyond lip of plate. Tuck overhang under itself; folded edge should be flush with edge of plate. Crimp dough evenly around edge of plate using your fingers. Wrap dough-lined plate loosely in plastic and refrigerate until dough is well chilled, about 1 hour.

for the topping

 Meanwhile, stir all ingredients in bowl until no dry spots remain and mixture forms clumps. Refrigerate until ready to use (mixture will firm up as it chills).
When ready to bake, adjust oven rack to lower-middle position and heat oven to 375 degrees. Line rimmed baking sheet with parchment paper.
Combine 2 tablespoons cornstarch and 2 tablespoons reserved cherry juice in small bowl. Bring ⅔ cup reserved cherry juice to boil in small saucepan over medium-high heat. (Discard remaining cherry juice or save for another use.) Whisk in lemon juice, almond extract, and cornstarch mixture and cook, whisking constantly, until thickened and glossy, about 1 minute. Remove from heat.
Whisk remaining ½ cup sugar, salt, and remaining 2 tablespoons cornstarch together in large bowl. Add reserved drained cherries and toss until evenly coated and no dry sugar remains. Add thickened cherry juice mixture and toss to coat. Transfer mixture to dough-lined plate and spread into even layer. Break chilled topping into pea-size crumbs and distribute evenly over cherry mixture.
Bake pie on prepared sheet until top is golden brown and juices are bubbling, about 1 hour. Let pie cool on wire rack for at least 4 hours. Serve.