Bring a large pot of salted water to a boil and cook the whole wheat spaghetti according to package directions until al dente.
While the pasta cooks, whisk together the whole egg, egg whites, grated parmesan, and black pepper in a small bowl until well combined.
In a large skillet over medium heat, sauté the diced pancetta until it becomes crispy and golden brown.
Add the minced garlic and frozen peas to the skillet with the pancetta, sautéing for 2 minutes until the peas are bright green and heated through.
Reserve 0.25 cup of the starchy pasta water, then drain the spaghetti.
Immediately add the hot pasta to the skillet with the pancetta and peas, tossing to combine while still 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, tossing constantly and adding a splash of the reserved pasta water as needed to create a creamy, emulsified sauce.
Serve immediately with an extra crack of black pepper if desired.