The CRC has received inquiries about their Royo Bread as far as to what brachos should be made. They tell us that the bracha on the bread is Hamotzi (as it does include some grain requiring the bracha) and Netilas Yadayim & Birchas Hamazon as well.
One slice of bread includes roughly a K’zayis of flour. Therefore:
It is recommended for a person to eat at least 1.5 slices so that they can consume the required amount for washing and bentching.
If a person only eats a single slice, they should wash their hands and not make the bracha “Al Netilas Yadayim (as it is less a K’beitzah). However, they are halachically required to say Birchas Hamazon (as it is more than a K’zayis”.