To cook the pasta- (use instructions on box)

OR

Boil the water in a pan. Once it starts boiling, add pasta shells, salt and oil to it.
In about 10 minutes, pasta is boiled.
Make sure it’s little bit undercooked.
Save 1/4 cup pasta water and discard remaining.

In a pan, add olive oil and butter.
Once butter starts melting, add the cornflour and mix it well together. In about 2 mins or so, cornflour will be cooked, and will be golden in colour.
Add 1/2 cup of milk and whisk it. Make sure there are no lumps. Then slowly add the remaining milk, cream and pasta water (as kept aside) and mix them well together.
Now add garlic powder, salt, oregano, paprika, black paper powder.
Mix together and bring it to boil.
Once starts boiling, reduce the flame and add cheese. Melt all the cheese and mix well. Make sure there are no lumps and your white sauce is ready.

In a pan, mix the boiled Wheafree pasta and already prepared sauce together with light hands.
Preferably use different pan than a saucepan (that you already have been using for the preparation of the sauce) as it will be boiling hot and it will cook your pasta more.

Add your white sauce pasta in a baking pan, make sure you use all the white sauce.
Add a layer of crushed potato chips and cheese. Top it off with a dollop of butter.
Make sure your pasta is not dry and it has additional sauce in it. Otherwise baking will make your pasta dry.
Preheat over to 180 degree Celsius. Bake the pasta for 5 mins and then grill for 3 mins. Serve it hot.