In a saucepan, combine cherries, sugar and cornstarch, let sit for about 10 minutes. Bring to a boil over medium heat, stirring constantly. Lower the heat and simmer for 5 minutes or until the juices thicken and become translucent. Remove from heat and stir in the butter and almond extract.
Pour filling into an un-baked 9-inch pie shell. Cover with top crust, cut away excess dough, seal and flute edges. Make several small slits in the top to allow steam to escape OR make a lattice top. Lightly brush with egg white and sprinkle with sugar.
Bake pie for 40 to 50 minutes, or until the filling is bubbly and the crust is golden brown. You may need to cover with foil, if the crust browns too quickly.
Cook’s Note: Use fresh sour cherries or canned. Do not use canned cherry pie filling. Papa's Pie Crust Recipe: http://www.cookingmamas.com/papas-pie-crust.html