Dice the guanciale into small pieces and cook in a cold skillet over medium-low heat for 10-15 minutes until golden brown and crispy.

Remove the crispy guanciale from the pan using a slotted spoon, leaving the fat in the skillet.

Optional: Sauté minced garlic in the skillet with a drizzle of olive oil for about 30 seconds.

Whisk together eggs, grated Pecorino Romano, grated Parmesan, and black pepper in a separate bowl.

Cook spaghetti in a pot of boiling salted water for about 8-10 minutes until al dente, reserving 1 cup of pasta water before draining.

Combine the drained spaghetti with the reserved guanciale fat in the skillet, tossing gently.

Add the whisked egg mixture to the spaghetti off the heat, tossing quickly to create a creamy sauce.

If the sauce is too thick, add reserved pasta water gradually while tossing to reach the desired consistency.

Stir in the crispy guanciale and combine until well-mixed.

Taste and adjust seasoning. Serve immediately, garnished with extra cheese and black pepper.