Melt butter in a medium-size saucepan with two beef bouillon cubes. Dice onions and add to pan. Saute over medium-high heat until bouillon cubes are dissolved and onions are caramelized. Turn off heat and set aside to cool to room temperature. After the onions are cooled, combine onion mixture, sour cream, garlic salt, and Worcestershire sauce. Refrigerate at least one hour before serving–with potato chips, of course!