Heat water in a deep vessel with salt and 1 tsp oil and when water starts boiling add fusilli pasta and cook till al-dente (just cooked).
Drain in a colander and rinse with water and keep aside.
Boil frozen corn in little water for a minute, strain and keep aside.
In a pan, heat 1 tbsp oil and saute garlic and then add chilli flakes.
Add onions and saute till little golden in colour. Don't over roast the onions.
Add in the bell peppers and frozen corn and saute for 1 minute. We have to keep the vegetables crunchy. Keep aside.
In a pan heat 1 tsp olive oil and butter.
Add in the all purpose flour and roast by continuously stirring it till aroma comes out and it is little golden in colour. Make sure there are no lumps.
Stirring continuously add in the milk, salt, white pepper, dried Italian herbs, oregano.
When it starts thickening add in the grated cheese and mix properly. Don't thicken the sauce too much.
Now switch off the gas and add in the veggies and give it a mix.
Now add in the boiled pasta and mix nicely.
Your cheesy pasta in white sauce is ready. Serve hot.
Note: you can use any cheese for making the sauce like mozzarella or cheddar as per your choice.