Hot Chicken Sandwich - Testing

 https://www.foodnetwork.com/recipes/rachael-ray/diner-style-hot-turkey-sandwiches-recipe-2043446

1 - I did not trust the process and forgot about the egg yolk. I couldn't understand why the roux wasn't thickening, so I added enough butter and flour to make it 1/4 cup butter and 1/3 cup flour. The sauce thickened immediately. That's when I realized that the egg yolk was supposed to finish the thickening. While the heavier roux did the job, I'd still like to try it with the egg yolk as there might be a difference if flavour; adding the taste of eggs and reducing the taste of flour, and possibly creating a silkier sauce. The flavor profile however was met with great approval.

3 Tbsps butter
Coarse black pepper
2 tablespoons flour
2 cups chicken stock

1/4 cup finely chopped fresh herbs, such as thyme, sage and parsley

About 3 1 Tbsps Worcestershire sauce
1 egg yolk
1 Tbsp Dijon mustard
Salt
A couple cups stock, to reheat sliced chicken
Sliced peasant loaf-style bread
Chopped fresh parsley, garnish

OPTIONAL : mashed potatoes or stuffing

1. For the gravy, melt the butter in a large skillet and season liberally with black pepper. 
2. Whisk in the flour until light golden in color. 
3. Then whisk in the stock and then add the herbs.
4. Stir in the Worcestershire and simmer slowly to thicken. 
5. IF you have a roast chicken and have any pan drippings, add the drippings now. 
6. Once the gravy lightly coats the back of a spoon, add a ladle of it to the egg yolk while beating with fork. Then add the yolk back to gravy to gloss it up, stir in. 
7. Add the mustard. Add salt to taste. 
8. While the gravy is simmering, heat up an additional couple cups of plain stock in a high-sided skillet. Thinly slice the chicken and add to the stock and leave only long enough to hot up.
9. Thinly slice the chicken and add to the finished sauce, heating it up only long enough to bring it up to the same temperature as the sauce.
10. For each sandwich, very lightly toast a slice of bread and place on a dinner plate. 
11. IF using mashed potato or stuffing, layer it on before the next step. 
12. Arrange the chicken over the bread and liberally ladle the gravy over the top of the sandwich and garnish with chopped parsley.