Heat a non-stick skillet to medium-high and start frying bacon.
After 2-3 minutes add the garlic cloves and continue frying until the bacon has browned, for about 7-10 minutes (or less if you like it softer).
Meanwhile, boil pasta in salted water for one minute short of cooking time. Drain and reserve 1 cup of cooking water.
Beat the egg with 1 tbsp water. Stir in 1 tbsp grated parmesan into the egg mixture.
Add the drained spaghetti to the pan with bacon and toss to coat the pasta with bacon fat.
Slowly start pouring the egg mixture into the pasta, tossing and swirling the spaghetti with tongs so that the egg breaks down. Continue until you run out of mixture, then pour a little of the reserved cooking water - keep tossing and turning.
Once all egg mixture is incorporated and the pasta looks moist and is al dente, you are done.
Season with ground black pepper and serve immediately.