Cheesy Chicken-Broccoli-Cauliflower Casserole

INGREDIENTS

1 10 ounce can

low-sodium cream of mushroom soup (optional)

skinless, boneless chicken breasts, cubed

2 10 ounce packages

frozen cauliflower and broccoli mix

2 tbsp

butter

1 1/2 cups

milk

3/4 tsp

salt

3 tbsp

all-purpose flour

1 1/2 cups

shredded Cheddar cheese, or more to taste

1 pinch

garlic powder, or to taste

1/2 cup

seasoned bread crumbs, or more to taste