Combine 3/4 cup sugar, cornstarch, cinnamon and 1 c. water in medium saucepan; stir mixture to remove lumps. Cook over medium heat, stirring constantly until smooth and thickened.
Remove from heat; stir in blueberries, 1/2 cup sugar, butter, almond extract and food coloring. (should be a deep purple color)
Pour blueberry mixture into the pastry shell. Cover with top crust. Trim edges of pastry; seal and crimp edges. Cut slits in top of crust for steam to escape, or make a basket weave crust. Bake at 425 degrees for 45 to minutes or just until golden brown. Yield one 9-inch pie.