Line a 9 inch pie plate with pastry. In a sauce pan combine sugar and flour. (Drain cherries reserving 3/4 cup juice.) Add the cherries, the reserved juice, and the extract to the sugar and flour mixture. Cook slowly until it thickens. Pour into pie plate. Place top crust on and cut slits in the top crust for the escape of steam. Bake at 400 degrees for 30 minutes or until crust is lightly brown.