Add pasta, water and salt in a mug. Cook for 4 minutes then pull out and stir. Add upto 1/4 cup more water if needed. Cook an additional 1 - 2 minutes at a time until cooked.
Stir in cheese and heavy cream and continue to microwave for 30 - 45 seconds. Give it a really good stir.
I like to top it with a sprinkle of parmesan cheese, salt/pepper and parsley.