In a medium saucepan combine the egg, half-and-half or light cream, and margarine or butter. Cook and stir over medium heat till mixture just coats a metal spoon (about 3-4 minutes). Remove from heat. Immediately stir in the Parmesan cheese and chives or green onions. Pour egg mixture over hot pasta and vegetables and toss to coat pasta. Transfer to a warm serving dish. Sprinkle with pepper. Serve immediately.
Testing Egg Mixture
Dip a spoon into the cooked egg mixture. The excess should drip off, leaving a creamy coating slightly thicker than milk. The coating should hold its shape when you wipe a finger across the back of the spoon.
Hold a bunch of chives with one hand (remove any damaged pieces). With kitchen scissors, snip off little tubes (about 1/4 inch long) into a small bowl.