Heat the oven to 450 degrees F.
In a cast iron skillet, melt the butter over medium heat and add the celery, onions and mushrooms. Cook until softened, about 5 to 8 minutes. Add the flour and cook until golden, about 2 minutes. Stir occasionally.
In a medium sized bowl, thoroughly combine the half and half and egg yolks. Slowly stir in the half and half mixture into the skillet, making sure to stir the entire time and not allow the liquid to boil. Add the cloves, lemon juice and salt.
Let the sauce warm thru and thicken, about 5 to 8 minutes. Stir in the chicken and top with the bread and gruyere. Place into the oven and bake for 10 to 15 minutes, or until the bread and cheese is golden. Serve immediately.