Heat oven to 350°F. Grease bottom and sides of 13x9-inch pan with shortening or spray with cooking spray; coat with flour. In large bowl, beat brown sugar, butter and egg with electric mixer on medium speed until blended, or mix with spoon. Stir in remaining bar ingredients. Spread in pan.
Bake 20 to 22 minutes or until top springs back when touched in center.
Meanwhile, in small bowl, mix all glaze ingredients with spoon until smooth and thin enough to drizzle. Drizzle over bars while warm. Cool completely, about 1 hour. For bars, cut into 8 rows by 6 rows.