Heat oven to 350°F.
In 1-quart saucepan, heat whipping cream, 3 tablespoons butter and 1 tablespoon corn syrup to a full boil over medium heat; turn off heat. Add dark chocolate chips; let stand 5 minutes without stirring. After 5 minutes, stir slowly with wire whisk until chocolate chips are melted and mixture is smooth and glossy; set aside.
In large bowl, stir together flour and 1/2 cup brown sugar. Cut in 1/2 cup cold butter, using pastry blender (or pulling 2 table knives through mixture in opposite directions), until mixture looks like coarse crumbs. Stir in oats and pecans. Press mixture into ungreased 15x10x1-inch pan. Bake 15 to 20 minutes or until crust is golden brown.
Meanwhile, in 2-quart saucepan, heat 1 cup butter, 1 cup brown sugar, 1/4 cup corn syrup, the salt and condensed milk to boiling over medium heat, stirring constantly. Continue boiling 5 minutes, stirring constantly. Pour over crust; spread evenly. Cool slightly, about 10 minutes.
Pour chocolate truffle topping over caramel layer; spread evenly. Cool 1 hour at room temperature; refrigerate at least 2 hours before serving. For bars, cut into 15 rows by 5 rows. Cover and refrigerate any remaining bars.