Heat oven to 425 degrees. Prepare pastry.
Mix sugar and flour. Stir in strawberries. Turn into pastry lined pie plate; sprinkle with lemon juice and dot with butter. Cover with top crust that has slits 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.