Mix sugar, flour and cinnamon. Stir in berries. Turn into pastry-lined pie plate. Dot with butter. Cover with top crust that has slits cut in it; seal and flute. Cover edge with 2- to 3-inch strip of aluminum foil to prevent excessive browning; remove foil during last 15 minutes of baking.
Bake until crust is brown and juice begins to bubble through slits in crust, 35 to 45 minutes.
I usually sprinkle some sugar on top after the pie comes out of the oven just because I like the look.