Steamed vegetables with béchamel sauce

several types of your favorite vegetables (potatoes, broccoli, cauliflower, Brussels sprouts, carrots, green beans, peppers, onions, etc)
mushrooms
ew chicken breast cut into small pieces or small meatballs
white sauce with the previous entry
All the ingredients clean, cut into very large pieces and place in a dish to be steamed. At the bottom put it, which requires the longest cooking (meat, potatoes, beans, onions, peppers). Cook 25-30 minutes. Spread béchamel sauce.