Rinse the chicken.
Boil the chicken in water with the bay leaf and garlic in a large stockpot until cooked through.
Remove the chicken from the stockpot, reserving the stock.
Let the chicken cool and then debone.
Add the carrots, potatoes, onion, (sherry if you are using this) to the reserved stock.
Cook over medium-high heat until the vegetables are tender.
Add the basil, mushrooms and peas.
Cook for 5 minutes longer.
Discard the bay leaf.
Melt butter in a medium saucepan.
Stir in the flour gradually.
Pour in the cream gradually, stirring until mixed.
Simmer until thickened, stirring constantly.
Add the cream mixture and chicken to the vegetables and broth, stirring well.
Simmer until mixture thickens.
Season with salt and pepper.
Roll out the pie pastry to a 1/8” thickness.
Place chicken mixture in two greased 9x13” casserole dishes.
Top each with pie crust. Cut a few slits in dough to vent steam.
Brush top with beaten egg yolk.
Bake at 350° for about 45 minutes or until browned and bubbly.
Makes two 9x13" casserole dishes.
Allow casseroles to rest about 5 minutes before cutting and serving.