Cook onion and mushrooms in some oil and keep aside

Slice the boiled potatoes in round shape

Preheat the oven at 180 degrees Convection mode

In a wok, put butter and add garlic paste followed by cornflour. Make sure no lumps are formed

Add milk and bring to boil

Add the grated parmesan cheese and mix till sauce is well formed and thick

Add a pinch of ajinomoto

Add salt and pepper to taste

In a Borosil square baking dish, line the slice potatoes, cover with the sauce and add cooked onion and mushroom on top.

Repeat the process so the top layer is covered with the sauce

Bake at 180 degrees for 15-20 minutes on Convection mode