Bring a large pot of salted water to a boil and cook the chickpea spaghetti according to package directions until al dente.
While the pasta cooks, finely dice the pancetta and mince the garlic clove.
Place the pancetta in a cold skillet and turn the heat to medium, cooking until the fat has rendered and the pancetta is golden and crispy.
In a small bowl, whisk together the whole egg, egg whites, grated Pecorino Romano, and black pepper until well combined.
Add the frozen peas to the boiling pasta water during the last 2 minutes of cooking time.
Before draining the pasta, reserve about 0.25 cup of the starchy pasta water.
Drain the pasta and peas, then add them to the skillet with the pancetta and garlic, tossing for 30 seconds 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 reserved pasta water as needed to create a smooth, creamy sauce.
Serve immediately in a warm bowl with an extra crack of black pepper.