Step 1
Bring a large pot of lightly salted water to a boil. Cook manicotti in the boiling water stirring occasionally until cooked through but firm to the bite 8 to 10 minutes. Drain.
Step 2
Place chicken and bay leaf into a saucepan and pour in enough water to cover; bring to a boil cover saucepan reduce heat to medium and simmer until chicken is no longer pink in the center about 20 minutes. Remove chicken from saucepan and place on a work surface to cool. Discard cooking water skin and bones. Finely chop chicken.
Step 3
Heat 1 tablespoon butter in a saucepan over medium heat; cook and stir mushrooms 1/3 cup chopped onion salt basil thyme and paprika until mushrooms are tender 5 to 10 minutes. Remove saucepan from heat and cool.
Step 4
Mix mushroom mixture eggs Parmesan cheese and chicken together in a bowl.
Step 5
Preheat oven to 350 degrees F (175 degrees C). Grease a 12x7-inch baking dish.
Step 6
Heat 2 tablespoons butter in a saucepan over medium heat; cook and stir 1/4 cup chopped onion until tender 5 to 10 minutes. Stir flour into onion until dissolved; add milk. Cook and stir mixture until sauce is bubbling and thickened about 5 minutes. Stir wine into sauce; add mozzarella cheese and stir until cheese is melted.
Step 7
Stuff the cooked manicotti with chicken mixture and arrange filled pasta in the prepared baking dish. Pour cheese sauce over pasta. Cover dish with aluminum foil.
Step 8
Bake in the preheated oven until cooked through 25 to 30 minutes.