1Heat oven to 350°F. In medium bowl, beat 3/4 cup softened butter and the brown sugar until creamy. Add flour and salt; mix until soft dough forms. Stir in nuts. Press in ungreased 9-inch square pan. Bake 25 to 30 minutes or until light golden brown. Cool 10 minutes.
2In medium microwavable bowl, microwave sweetened condensed milk and vanilla baking chips uncovered on High 1 to 2 minutes, stirring every 30 seconds, until chips are completely melted and mixture is smooth. Stir in dried pineapple. Pour over shortbread in pan. Refrigerate about 1 1/2 hours or until set.
3In small microwavable bowl, microwave chocolate chips, 1 tablespoon butter and the whipping cream uncovered on High 1 to 2 minutes, stirring every 30 seconds, until chips are completely melted. Spread over pineapple layer. Refrigerate about 1 hour or until set. For 36 bars, cut into 6 rows by 6 rows. Store covered in refrigerator.