- Heat oven to 350°F (325°F for glass dish).
- Stir together flour, sugar and cocoa in large bowl.
- Cut in butter until crumbly.
- Press firmly onto bottom of ungreased 13x9x2-inch baking pan.
- Bake 15 minutes; remove from oven.
- Meanwhile, in medium bowl, beat sweetened condensed milk, egg and vanilla until well blended.
- Stir in pecans.
- Spread mixture evenly over hot baked crust.
- Return to oven.
- Bake 25 minutes or until lightly browned.
- Cool completely in pan on wire rack.
- Cut into bars.
- Cover; store in refrigerator.