We did breakfast at Akershus which is a buffet. There is a cold buffet with pastries, fruit, smoked salmon, etc.. The hot food (eggs, bacon, sausage, potatoes) is brought to your table family style but you can ask for more of whatever you like so it's like a buffet.
We really enjoyed this breakfast - we got to meet 5 princesses in a very relaxed atmosphere and have a really good meal.