Lettuce with Hot Bacon Dressing

Fry bacon in a heavy medium saucepan over medium heat until crisp. Remove bacon to paper towels to drain; reserve drippings in pan.

Meanwhile, combine flour, sugar, mustard and salt in a small bowl; gradually beat milk into mixture. Add milk mixture to drippings in saucepan and bring to a boil, stirring constantly.

Beat yolk in bowl in which milk mixture was combined. Gradually beat about a quarter of the milk mixture into the egg, then return mixture to the saucepan and bring just to a boil. Remove from heat and stir in vinegar. Crumble bacon and fold into dressing.

Divide lettuce among 4 salad plates. Top with dressing and serve immediately.