Preheat oven to 400°F. Prepare pie crust as directed on package for two-crust pie, using a 9-inch pie plate.
Mix sugar, cornstarch and cinnamon in large bowl. Add berries and lemon juice; toss gently. Spoon mixture into pastry-lined pie plate. Dot with butter. Top with second pie crust. Seal and flute edge. Cut small slits in top crust.
Bake 50 to 60 minutes until crust is golden brown and filling is bubbly. Cool on wire rack.