1Heat oven to 350°F. In large bowl, beat butter and sugar with electric mixer on medium speed until creamy. Beat in egg until well blended. On low speed, beat in flour, salt and dry gelatin until soft dough forms. Press dough in bottom of ungreased 13x9-inch pan.
2Bake 11 to 14 minutes or until center is set. Cool completely, about 30 minutes.
3In resealable freezer plastic bag, mix chocolate chips and oil; seal bag. Microwave on High 30 to 45 seconds, squeezing chocolate in bag every 15 seconds, until smooth. Cut 1/4-inch tip from corner of bag; drizzle chocolate over bars. Let stand about 1 hour or until chocolate is set. For bars, cut into 8 by 4 rows; cut each bar in half diagonally to make triangles.