Thaw cherries until most of the free ice has disappeared. Drain off the juice; measure 1c. juice and stir it into mixture of sugar, tapioca and cornstarch in saucepan. Heat rapidly until thickening is complete. Boiling is not necessary. Set aside to cool.
Add cherries and almond extract to cooled, thickened juice. Pour filling into pastry-lined 9" pie pan. Cut vents in top crust; cover pie, seal and flute edge.
Bake in hot oven (425°) 30 to 35 minutes, or until nicely browned. For a brown undercrust, bake on lowest oven shelf.