1. Fill a large deep frying pan with water and 2 tsp salt and bring to the boil.
2. Meanwhile in a small saucepan on low medium heat render off pork fat, once crispy, remove with a slotted spoon to paper towel.
3. Bring the same small saucepan to medium-high heat and season scallops on both sides with salt and pepper. Sear until golden brown on both sides. Rest aside until required.
4. Boil pasta until just under al dente, then drain from pan and reserve one cup of pasta water. To that pan (off the heat) return spaghetti, cheese, egg yolk, black pepper and guanciale. Mix well, slowly adding the pasta water to create the desired consistency of sauce.
5. Plate pasta and top with seared scallops and serve.