Heat oven to 350°. Line 13 x 9 x 2-inch baking pan with nonstick foil (step A, below), leaving overhang.Advertisement
In large glass bowl, heat butter and chocolate in microwave on HIGH for 2 minutes; stir until smooth (step B). Let stand 5 minutes to cool slightly. Whisk in sugar, eggs, flour and vanilla. Stir in pecans and half of the chocolate chips (1 cup). Transfer batter to prepared pan. Sprinkle with remaining 1 cup chocolate chips (step C).
Bake at 350° for 35 minutes, until top is dry to the touch. Let cool completely in pan on wire rack. Lift brownie from pan with foil. Cut into squares and serve.
To line pan, place it upside down on counter and shape foil over outside. Flip pan over and tuck shaped piece inside.
No need to chop chocolate before microwaving. Though squares will look solid after heating, stir until smooth and lump-free.
Scatter remaining chips over batter for double the chocolate in every bite!