Cut the chicken and onion into suitable-sized pieces. Melt the butter in a pot (or frying pan) and saute the chicken and onions.
Once the onions have wilted, stop the heat. It's okay if the chicken hasn't cooked through. Add the flour and mix until no longer floury.
Add the milk, soup stock, and macaroni and use a wooden spatula to mix well. Turn on the heat to low and mix slowly, simmering until creamy.
Once it's become creamy, transfer to a gratin dish, and top with the pizza cheese and grated cheese. Bake in the oven or in an oven at 250℃ for 10-12 minutes.
Story Behind this Recipe
A long time ago I used a premix gratin powder where you didn't have to boil the macaroni separately. Lately there are more quick-boil macaroni varieties available, so I made this thinking that it wasn't necessary to boil the macaroni.
Quick-boil macaroni can be used as-is without having to boil it separately. However, the macaroni will soften and won't have a bite, so if you want to enjoy that then use gratin macaroni, boiled separately. If adding spinach or broccoli, either boil or microwave, then add in Step 4.