1Heat oven to 350°F. Beat sugar, butter, vanilla and egg in large bowl with electric mixer on medium speed, or mix with spoon. Stir in flour, baking soda and salt.
2Reserve 3/4 cup dough for topping. Press remaining dough in bottom of ungreased 13x9-inch pan. Place 4 mints end-to-end on dough across narrow end of pan. Continue adding mints to make 7 rows of 4 mints each. Press mints lightly into dough. Crumble reserved dough over mints.
3Bake 20 to 23 minutes or until light brown. Cool completely to set chocolate, about 45 minutes. For bars, cut into 7 rows by 4 rows.