Spaghetti Carbonara

I have been wanting to try making pasta with carbonara sauce for quite some time now. It is quite a simple and basic dish, but the idea always intrigued me. A sauce made with eggs that are cooked once tossed with the hot pasta? Interesting! I didn't really follow a particular recipe for this one, but just sort of made it based on several different recipes I read. Therefore, I don't have any precise measurements - just eyeballed amounts  based on taste preferences.  I also made a vegetarian version - usually carbonara begins by frying up some bacon or pancetta, and using the flavorful oil in the sauce base, as well as the crispy meat in the finished dish. I omitted this, but I did add some breadcrumbs for a little extra flavor. Another change I made, since I am paranoid about food poisoning and proper cooking, was to bring the sauce to a boil, instead of removing the spaghetti from the heat and then stirring in the sauce. This not only ensures the eggs are properly cooked, but also thickens the sauce. I have given approximate measures, and the procedure below for about four servings, though amounts may be tailored to suit different amounts or tastes. 

Ingredients
spaghetti (4 servings)
butter (1 Tablespoon)
olive oil (1 Tablespoon)
chopped onion (1/2 small)
dry breadcrumbs ( 2 Tablespoons)
whipping cream (200 mL)
eggs (2 large)
grated Parmesan cheese (3 Tablespoons, plus extra for topping)
salt (to taste)
ground black pepper (to taste)

Cook spaghetti according to package directions. Meanwhile, heat the butte rand oil in a small frying pan over medium heat. Sautée the onion until softened, but do not brown. Add the breadcrumbs and stir for a few minutes until aromatic.
Beat the cream, eggs, Parmesan, salt and pepper together in a small bowl. 
Drain the spaghetti, return to pot, then immediately stir in the onion mixture and the cream mixture. Stir for a few minutes to coat, then turn heat to high and cover. Bring the mixture just to a boil, stir again, and serve topped with more Parmesan.