The only trick to Carbonara is tempering the egg yolks to ensure you do not end up with scrambled eggs. For the brightest color, I use Araucana eggs, which are widely available at Whole Foods and farmer markets. The eggs have a greenish-blue tint to the shell and the hens that lay them are often fed marigolds which make the egg yolks intensely bright yellow-orange. Many recipes for carbonara include cream—I never add cream. The creamy quality of the sauce should come from the tempered eggs emulsifying with the cheeses and pasta.