Bring a large pot of water to a boil. Meanwhile, cook the bacon in a large skillet. Remove bacon and set on a paper towel to cool. Reduce heat and gently saute the garlic clove in bacon grease until aromatic. Remove garlic and discard. (This gives the carbonara a subtle garlic flavor. If you prefer more garlic, mince the garlic before sauteing and don't remove it.) Remove the pan from the heat and allow to cool (you'll mix the pasta in this pan in a few minutes).

Add the spaghetti to the boiling water and cook until al dente. Crack the egg in a small bowl and and whisk it with half of the Parmesan cheese. Working quickly, strain the pasta. Add the pasta and the egg mixture to the pan used to cook the bacon and whisk, whisk, whisk them together for about 20 seconds. Sprinkle pasta with crumbled bacon, the remaining Parmesan and pepper and salt. Serve immediately.