Step 1: Prepare the Pasta : Bring a large pot of salted water to a boil. Add spaghetti and cook according to package directions until al dente. Before draining, reserve 1 cup of pasta water (it’s key for the sauce). Drain the pasta and set aside.

Step 2: Cook the Pancetta (or Bacon) : In a large skillet, cook pancetta over medium heat until crispy (about 5–7 minutes). If using bacon, add 1 tbsp olive oil before cooking. Add minced garlic (optional) and sauté for 30 seconds until fragrant. Remove from heat and set the pan aside — don’t drain the fat; it adds flavor.

Step 3: Prepare the Carbonara Sauce : In a mixing bowl, whisk together eggs, yolks, and grated Parmesan until smooth. Season generously with black pepper (about ½ tsp). Set aside at room temperature.

Step 4: Combine Everything : Return the skillet with pancetta to low heat. Add the cooked pasta and toss to coat in the fat. Remove the pan completely from heat (this step is crucial to prevent scrambled eggs). Slowly pour in the egg and cheese mixture, tossing quickly to create a creamy sauce. Gradually add reserved pasta water as needed (start with ¼ cup) until the sauce is silky and coats the pasta. Taste and adjust with salt and pepper.

Step 5: Make the Garlic Bread : Preheat oven to 375°F (190°C). Mix softened butter, minced garlic, parsley, and salt in a bowl. Slice the baguette in half lengthwise and spread the butter mixture evenly. Sprinkle Parmesan on top if desired. Place on a baking sheet and bake for 10–12 minutes, or until golden and crispy. Slice and serve warm.