Take a big pot for boiling the pasta .Fill it with sufficient water .Add salt to it .
Boil pasta till al dente. It means it should have a bite .If you want softer pasta go ahead .
Drain the pasta ,but reserve one cup of pasta water.
Take a pan .Heat it .Add oil and butter to it.
Now add onion and saute it .After 1 minute add ginger, garlic ,cashews and saute for 2-3 minute till they look cooked.
Add all the spices to it and saute for 2 minute.
Add tomato puree or chopped tomato .Saute it for 1-2 minutes till they look mushy and cooked.
Grind this spice mix in to a puree. Keep it aside.
Now take the same pan again .Add butter .Heat it .
Add pureed sauce and cream to it . Stir on low flame. Add pasta to it .Mix it nicely.
Add red pepper flakes and check the seasoning .If you need to add more add ,if its salty then add little bit of cream.
If consistency is thin for your taste ,cook it little more ,if its thick add just a little bit of pasta water.
Garnish with Cilantro leaves and serve .I am sure you will enjoy this Indian Version of Pasta.