Rinse quinoa really well to remove bitter coating.
Add quinoa to a saucepan, along with the chicken stock (reserve 1/4 c), salt, dry mustard and pepper.
Bring to a boil then reduce heat and simmer for 15-20 minutes until all liquid has been absorbed. Stir well.
Mix quinoa and roasted peppers together, add in reserved chicken stock, and 2 cups grated cheese.
In separate bowl mix together Panko and Parmesan for topping
Put quinoa and veggie mixture into casserole dish
(If making into a freezer meal, freeze at this point along with a bag of topping mixture. Thaw fully on day you want to serve and continue with next step.)
Top casserole with breadcrumb and cheese mixture.
Bake at 375 in preheated oven for 30 minutes until golden
Let cool 10 minutes before serving.