One Pot Chicken and Mushroom Tetrazzini

butter

chicken breast (boneless and skinless, cut into cubes)

mushrooms (sliced)

salt and pepper

garlic powder (optional)

all-purpose flour

chicken broth (low sodium)

milk (I used 2%)

fettuccine or spaghetti (uncooked)

frozen peas

Parmesan cheese

parsley for garnish