To confit basically means to slow-cook an ingredient in fat. The term is often associated with duck confit, but can be employed for a host of ingredients. Confiting egg yolks is a modern technique, great for adding a little cheffy flair to home-cooked dishes. Alternatively to this method you can confit egg yolks sous vide.
You can use bacon fat or different flavoured oils, such as rosemary or garlic, as the confit – this adds another flavour dimension to the dish that you can use to complement other ingredients on the plate.