Helen, I think he is eating it too fast and that's why he pukes. Fister does it too when I give him something really yummy. Your plan of giving him less at a time will probably work.

Do you know the Whiskas pouches, the ones with gele? Fister loves those, but I give him a third of one at a time and pour a bit of boiled water in. He licks that and the gele off and leaves the rest.

Have a good time with your friend!