In fact, you can buy the ingredients at your local supermarket.
What, exactly, is it?
"Chocolate and peanut brownies."
Mr Conway has eaten plenty in his time and had some on hand at his 100th birthday celebrations yesterday.
He marked the occasion with family at his Don St home, while admiring birthday cards from the Queen, Governor General Dame Patsy Reddy, Prime Minster Jacinda Ardern, Waitaki MP Jacqui Dean and Minister for Seniors Tracey Martin.
Mr Conway did not expect such a fuss, despite the impressive milestone.
"I thought it was going to be very quiet," he said.
"People were coming up to me saying `I believe it's your 100th', people were shaking my hand, so it's been quite interesting."
Mr Conway was born in London and immigrated to New Zealand with his family aged 4.
He lived in Dunedin for most of his life and moved north to Oamaru 24 years ago.
Mr Conway worked in a woollen mill in Dunedin before the outbreak of World War 2.
He enlisted as a driver and eventually reached the rank of gunner, which he said he ended up with by default, with the 8th Reinforcements of the 6th Field Regiment, New Zealand Artillery, serving in Egypt and Italy.
However, he did not return home for several months afterwards.
Along with 17 others, he carried out the grim task of transferring the bodies of those killed in action that had been buried in makeshift graves to military cemeteries in Eastern Europe.
He eventually returned to Dunedin and tried his hand at carpentry.
He did not fancy that and ended up working with the postal service, and spent 27 years at the Princes St post office, in Dunedin, until his retirement.
He said he has had a good life, and would not change much about it.
"Life's been pretty good to me."
