Heat oven to 350°F. In large bowl, combine sugar, brown sugar, margarine and peanut butter; beat until light and fluffy. Add milk, vanilla and egg; blend well.
Lightly spoon flour into measuring cup; level off. Add flour, baking soda and salt; mix well. Press dough in bottom of ungreased 13x9-inch pan.
Bake at 350°F. for 19 to 24 minutes or until edges are golden brown.
Immediately press milk chocolate candies into bars, forming 5 rows of 8 candies each. Cool 1 hour or until completely cooled. Cut into bars with 1 milk chocolate candy in center of each.