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, place the diced pancetta in a cold skillet and turn the heat to medium, cooking until the fat renders and the pancetta is crispy.
In a small bowl, whisk together the whole egg, liquid egg whites, grated parmesan cheese, and black pepper until well combined.
Mince the garlic and add it to the skillet with the pancetta for the last 60 seconds of cooking until fragrant.
Reserve 0.25 cup of the starchy pasta water, then drain the pasta and add it directly to the skillet with the pancetta, turning the heat to low.
Add the baby spinach to the skillet and toss with the hot pasta until it just begins to wilt.
Remove the skillet from the heat entirely; slowly pour in the egg mixture while whisking or tossing constantly to create a creamy sauce without scrambling the eggs.
Thin the sauce with a splash of the reserved pasta water if needed and serve immediately with an extra crack of black pepper.