1. Stir together first 5 ingredients in a large mixing bowl. Add butter, stirring until mixture is crumbly. Reserve half of mixture (about 2 3/4 cups). Press remaining half of mixture into bottom of a lightly greased 13- x 9-inch pan. Sprinkle evenly with chocolate morsels, and, if desired, pecans.
2. Microwave caramels and half-and-half in a microwave-safe bowl at MEDIUM (50% power) 3 minutes. Stir and microwave at MEDIUM 1 to 3 more minutes or until mixture is smooth. Let stand 1 minute. Pour evenly over chocolate morsels. Sprinkle evenly with reserved crumb mixture.
3. Bake at 350° for 30 minutes or until light golden brown. Cool in pan on a wire rack. Cut into bars.