1Heat oven to 350°F. In large bowl, beat butter and brown sugar with electric mixer on medium speed until well blended. Beat in egg until well blended. Beat in molasses until creamy. On low speed, beat in remaining bar ingredients until soft dough forms. Press dough in bottom of ungreased 13x9-inch pan.
2Bake 15 to 18 minutes or until edges look dry and center springs back when touched gently with finger. Cool completely, about 1 hour.
3In small bowl, mix granulated sugar and 1/4 teaspoon cinnamon. Spread frosting over bars; sprinkle with cinnamon-sugar mixture. For bars, cut into 6 rows by 4 rows.