Sauté chopped onion in butter then add shredded chicken breast.

Add frozen vegetables and sauté for another 2 minutes.

Mix all purpose flour and all purpose cream and add to mixture. (You can replace cream with chicken stock if you don’t want it too creamy)

Add cheese and turn off the heat when the cheese melts.

Flatten the mixture in a butter greased baking dish.

Top the dish with the mashed potato completely covering the top.

Brush the mashed potato with egg wash and bake under 250 degrees for 10 to 15 mins or until the mashed potato turns golden brown.