Preheat oven to 425F and grease a 10x10 casserole dish. Keep butter for biscuits cold in the fridge while you prep the rest of the casserole.

Cut chicken breast into bite sized cubes and place in the casserole dish with frozen peas and carrots.

In a small sauce pan, heat 3 tbsp butter for casserole over medium heat until just melted. Reduce heat to low and whisk in the 3 tbsp of all purpose flour into the butter until a thick paste is formed. Slowly pout in the milk and chicken broth whisking constantly. 

Mix in the salt, pepper, parsley and garlic powder and allow the mixture to simmer lightly while you prepare the biscuits.

Mix all purpose flour, salt, and baking powder together in a bowl. Cut the butter into small cubes and add to the bowl. Mix butter into the dry ingredients using a pastry cutter until it is evenly incorporated but not melted at all. If you do not have a pastry cutter you can use your fingertips to break the butter up and mix it in.

Mix the cold milk into the dough with a wooden spoon. Knead the dough together just until there are no wet spots and set to the side.

Take the simmering cream mixture from the stove and pour over the chicken and veggie in the casserole dish. Mix to combine.

Take the biscuit dough and drop in small clumps over top of the casserole to form a crust, it is okay if there is space between the biscuits.

Bake at 425F for 30 minutes. Allow to cool slightly and serve!