In a bowl, cream together sugar and butter. Add eggs one at a time, and beat after each addition. In a bowl, sift together flour, baking powder, and salt; add alternately with milk to the creamed sugar mixture. Stir in chopped cranberries.
Spoon into 12 paper-lined muffin cups, filling 3/4 full. Bake 25 to 30 minutes. Makes 16 muffins.