Cook the pasta in a large pot of well-salted boiling water according to the package instructions.
Drain the pasta well, reserving ⅓ cup of the starchy cooking water.
Meanwhile, cook the bacon slices in a large skillet until crispy, about 3-5 minutes. Remove the bacon and place it on paper towels to drain. Chop into bits.
Remove all but 1 tablespoon of bacon grease from the large skillet. Toss the garlic into the large skillet with the bacon grease.
Cook garlic for 45 seconds, stirring constantly.
Add the hot, drained spaghetti to the pan and toss for 2 minutes to coat the strands in the bacon grease/olive oil/garlic. Side Note: The pasta must be hot when adding the egg and Parmesan mixture so that the heat of the pasta cooks the raw egg in the sauce.
Beat the egg and Parmesan together in a mixing bowl, stirring.
Remove the pan from the heat and pour the egg/cheese mixture into the pasta, stirring quickly until the egg thickens but does not scramble.
Thin the sauce with some reserved pasta water until it reaches the desired consistency.
Finish the dish by adding the peas and bacon bits, then season with freshly cracked black pepper. Season with sea salt if needed, add fresh parsley, and mix well.
Place into a serving bowl and serve immediately. Enjoy.