1Heat oven to 350°F. Grease bottom and sides of 13x9-inch pan with shortening or spray with cooking spray. In 3-quart saucepan, heat caramels and milk over low heat, stirring frequently, until caramels are melted and smooth.
2In 2-quart saucepan, melt butter over low heat; remove from heat. Stir in sugar, vanilla and eggs until well blended. Stir in flour, cocoa and salt. Stir in 1 1/2 cups of the chocolate chunks and 1 cup of the pecans. Spread evenly in pan.
3Gently and evenly drizzle melted caramel over batter, preventing large pockets of caramel and preventing caramel from reaching bottom of bars. (Caramel can cover entire surface of batter.) Bake 35 to 40 minutes or until set.
4In 1-quart saucepan, heat remaining 1/2 cup chocolate chunks and the oil over low heat, stirring frequently, until smooth. Drizzle over warm brownies. Sprinkle with remaining 1/2 cup pecans; press in lightly. Cool 20 minutes. Refrigerate about 1 hour 30 minutes or until chocolate is set. For brownies, cut into 6 rows by 4 rows. If refrigerated longer, let stand at room temperature 20 minutes before serving.