Heat oven to 325°F.
Combine butter, powdered sugar and brown sugar in bowl. Beat at medium speed, scraping bowl often, until creamy. Add flour, baking powder and salt; beat at low speed until well mixed.
Press dough evenly into 8-inch square baking pan lined with aluminum foil; prick with tines of fork every 1/2 inch. Bake 25-30 minutes or until golden brown. Lift cookies from pan using aluminum foil. Immediately cut into 20 (approximately 4x1/2 inch) sticks. Cool completely.
Place caramels and half & half in microwave-safe bowl. Microwave, stirring twice, 1-2 minutes or until caramels are melted. Dip ends of shortbread sticks into melted caramel mixture; roll in pecans. Place onto waxed paper; let stand until set.
For gift giving, wrap each shortbread stick in clear plastic food wrap or cellophane gift bags; tie ends with decorative ribbon.