Thing One's classic casserole

The holidays have started, and Thing One decided to help me in the kitchen. Since he loves casseroles, I helped him rustle this meal up.

200 gms pasta
1 cup milk
1 tbsp cornflour powder
1/3 cup cheese, grated
10 button mushrooms, sliced in half
1 red bell pepper, roughly chopped
6 pods garlic, peeled
10 olives, pitted
2 tbsp basil leaves
Salt and pepper to taste
1 tbsp cooking oil

Method:
Cook the pasta according to the instructions on the pack, drain, wash with cold water and keep aside.
While the pasta is cooking, heat the oil, add the garlic pods and saute for 1-2 minutes. Add the bell peppers and mushroom, and saute till well browned. Add salt to taste, mix well and keep aside.
To make the white sauce, heat the milk, make a paste of cornflour with milk, mix well, and let it simmer on a low flame till the sauce attains desired consistency. Add salt and pepper to taste, and mix in 1/3 of the quantity of cheese. Add the torn basil leaves, and keep aside.
Chop the olives and mix well with the cooked pasta.
In an ovenproof bowl, put a layer of cooked pasta, followed by a layer of mushrooms, and a sprinkling of cheese. Repeat till all the pasta and mushrooms are used up, and top it with a layer of cheese.
Pour the white sauce over the bowl.
Bake in oven at 180 degrees for 5 minutes till the cheese melts. Enjoy.