Boil spaghetti in salted water until al dente, reserving 0.5 cup of pasta water.
Crisp chopped bacon in a skillet over medium heat.
Whisk eggs and grated parmesan cheese together in a bowl.
Toss hot drained pasta with cooked bacon, then remove pan from heat.
Quickly stir in egg mixture and reserved pasta water to create a creamy sauce without scrambling eggs.