HEAT oven to 350 degrees F. Combine flour, brown sugar and egg in medium bowl; cut in butter with pastry blender or 2 knives until mixture resembles coarse crumbs. Stir in peanuts. Reserve 2 cups crumb mixture. Press remaining mixture on bottom of ungreased 13 x 9-inch baking pan.
BAKE 15 minutes or until lightly browned.
BEAT sweetened condensed milk, peanut butter and vanilla with electric mixer in large bowl. Spread over partially baked crust; top with reserved crumb mixture.
BAKE an additional 25 minutes or until lightly browned. Cool. Cut into bars. Golden Peanut Butter Bars make a nice addition to a cookie jar or gift tin.