"Chicken and Shrimps Macaroni Gratin"

I've learned this recipe from Japanese cooking book, this is the common way of how the Japanese cook gratin recipe,some are made with vegetables such as mushroom, broccoli, spinach or assorted seafoods like shripms,scallops, or squid,and making their own original white sauce using butter, fresh milk, flour and seasoned with some spices, this is very simple and easy to prepare, please give a try to this cheesy, creamy and delicious Chicken and Shrimps Macaroni Gratin recipe! ENJOY!

                                             Chicken and Shrimps Macaroni Gratin
                                (please watch the video below for cooking procedure)

                                                                   Ingredients:
                                         100 grams macaroni (boiled0
                                             1 cup shrimps (de shelled,devein and boiled)
                                         300 grams chicken breast (cut in cubes)
                                          1/2 cup chopped onion
                                                broccoli (boiled)
                                                grated cheese
                                               salt / ground black pepper / nutmeg
                                                                (white sauce)
                                           70 grams butter
                                           70 grams white flour
                                         4 to 5 cups fresh milk