1 ½ cups (360 milliliters) grated pecorino cheese, plus more for serving
1 tablespoon (15 milliliters) ground black pepper, plus more for serving
Salt for boiling pasta
½ cup (120 milliliters) diced guanciale (or substitute with pancetta)
Put spaghetti in mildly salted boiling water to cook until al dente.
Meanwhile, whisk egg yolks in a large bowl until smooth. Stir in pecorino and ground black pepper.
Heat diced guanciale in olive oil over medium heat until crispy. Remove from heat.
When pasta is al dente, remove from boiling water (reserving pasta water) and add to pan with guanciale. Add some of the reserved pasta water. Add egg mixture and stir for one to two minutes, cooking with the residual heat of the pan.
Serve swirled into mounds along with extra pecorino and ground black pepper.