Bring a large saucepan of water to a boil. Heat a medium skillet over medium heat. Add the olive oil and pancetta to skillet, and cook until the pancetta is browned, 3 to 4 minutes. Remove skillet from heat, and keep warm.
Cook spaghetti in boiling water until al dente, about 8 minutes. While spaghetti is cooking, whisk cream, egg yolks, Parmesan, salt, and pepper in a medium bowl until combined. Drain pasta, and return to saucepan. Immediately stir in egg-and-cheese mixture until well combined. Add warm pancetta and fat from pan. Toss well. Thin sauce with additional cream, if necessary. Serve immediately, garnished with grated Parmesan cheese.