Line 13” by 9” baking pan with foil, extending foil over rim.
Prepare Creamy Polenta as directed but use only 3½ cups boiling water and cook until mixture is very thick and indentation remains when spoon is dragged through polenta, 30 to 35 minutes.
Stir in Parmesan and butter as directed.
Spoon mixture into prepared pan, smoothing top.
Refrigerate until very firm, at least 1 hour.
Preheat broiler.
Lift foil with polenta from baking pan; place on cookie sheet.
Cut polenta into 16 triangles; separate triangles.
Melt 1 tablespoon butter or margarine and combine with ½ teaspoon chopped fresh rosemary or ¼ teaspoon dried rosemary; brush onto polenta wedges.
Broil 5 to 7 inches from heat source until lightly browned and heated through, about 10 minutes.