Bring a large pot of water to a boil and season generously with the sea salt.
Add the spaghetti to the boiling water and cook until just al dente, according to package directions.
While the pasta cooks, add the diced pancetta to a cold skillet and turn the heat to medium, rendering the fat until the pancetta is crisp and golden.
In a small bowl, whisk together the liquid egg whites, the large egg yolk, grated Pecorino Romano, and freshly cracked black pepper until well combined.
Reserve about 0.25 cup of the starchy pasta cooking water, then drain the spaghetti.
Add the hot pasta directly into the skillet with the pancetta and its rendered fat, tossing to coat thoroughly over low heat.
Remove the skillet from the heat entirely to prevent the eggs from scrambling.
Slowly pour the egg and cheese mixture over the pasta while stirring constantly and vigorously to create a creamy, glossy sauce.
Add a splash of the reserved pasta water if needed to reach your desired consistency.
Garnish with fresh parsley and an extra crack of black pepper before serving immediately.