Step 1

If using meat drippings, remove the meat and lower the heat to medium. If not using meat drippings, heat a large frying pan to medium heat and melt 2 tablespoons of butter. Add leeks to the skillet. Make sure to move the leeks around in order for them not to burn.

Step 2

While the leeks are cooking add some finely chopped garlic and stir in well. Once the leeks have softened, stir in 2 tablespoon flour and then gradually add the stock and milk.

Step 3

When the broth starts to simmer, turn the heat to low and allow the sauce to thicken, about 15 minutes, stirring occasionally. At this point you can also add your protein back to the pan to cook it in the sauce.

Step 4

Once the sauce has thickened, add 1 teaspoon of ground mustard and 3 tablespoon of sour cream into the chicken and leek sauce.

Step 5

Squeeze the juice of half a lemon into the sauce and season with salt and pepper to taste. Finish by stirring in some fresh tarragon leaves.