The cans of dessert exploded "like fireworks" after the a blaze broke out on his HGV.
The driver was unaware that his lorry, carrying 26 tonnes of Ambrosia custard and rice pudding to a local supermarket, was on fire and motorists were forced to flag him down.
He eventually stopped on the A382 in Chagford, Devon, and fled the truck seconds before 60,000 cans began exploding "like thousands of gunshots".
Fire crews raced to the blaze but the desserts were too well alight and the whole lorry was consumed in just 20 minutes.
Eyewitness Jill Pendleton, who runs a holiday booking company, captured the spectacle on her camera.
She said: "The first we knew about it was a whiff of smoke and burning sugar and then suddenly it just erupted.
"It was incredible how quickly the fire caught hold - the whole thing was over in less than 20 minutes.
"When the heat reached the tins they started to explode and we could hear what sounded like thousands of gunshots. It was quite a fireworks display.
"There were two huge explosions which we think were either the airbags or the diesel tanks.
"The fire crews got here very quickly but there wasn't much they could do as the contents had burned out. The driver seemed very shaken."
No-one was injured in the fire. Local delivery firm Thompsons, which owns the lorry, were unavailable for comment yesterday.
A spokesman for Devon and Somerset Fire and Rescue Service said the road was closed for six hours while debris was cleared.
He said: "On arrival the crews found the lorry carrying rice pudding to be well alight on the highway. The incident was believed to be accidental."
