In a heavy-bottomed saucepan melt the butter over medium heat. As soon as the butter begins to bubble (don't let it brown), add the flour and cook together for 1 to 1 1/2 minutes.
Slowly whisk the chicken stock into the butter-flour. Stick the clove into the onion an add to the sauce along with the bay leaf. Simmer for 30 minutes, stirring now and then, and skimming as needed. Remove the onion and bay leaf before using.Servings: 4