A young cook returning home from work was shot dead in cold blood yesterday by a heartless thug — who stole his iPhone but ignored his wallet full of cash.

Hwangbum Yang, 26, had finished his shift at The Modern, a restaurant in the Museum of Modern Art, and was only two blocks from his apartment in the Riverdale section of The Bronx when the killer attacked at about 12:32 a.m.

Yang, a culinary-school graduate who taught Sunday school, was sent sprawling facedown after being blasted in the chest.

The thug then kicked his body over and rummaged through his pockets, a witness said.

“He stopped and sort of squished something with his foot, and then I realized it was a person because he lifted [Yang’s] arms up a little,” said the witness. “He did it so casually — that’s what is so scary.”

The witness said the thug, who was wearing a gray hoodie, made his getaway in a waiting silver minivan. He was still at large last night.

The slaying cut short the South Korean immigrant’s dream of reaching the top of the culinary world.

“He dreamed of becoming a famous chef here in New York so that he could go back to Korea and be very successful,” his sobbing mother, Hyun Sub Yang, 50, said through a translator.

She clutched some pieces of Yang’s clothing — holding on to any reminder of her son — as she left her home to go consult with her pastor about where to bury her only boy.

Earlier, the family went to the scene where Yang was shot, the witness said.

“It was so heartbreaking,” the witness said, adding that Yang’s sister fell to her knees, sobbing.

The shooting occurred on Cambridge Avenue near West 232 Street.

“If you’re going to rob someone, why not just take the money? Why do you have to take someone’s life?” cried his uncle, Jun Lee.

The victim’s heartbroken family recalled Yang as a humble, churchgoing young man who used to volunteer teaching children at St. John Nam Church on White Plains Road.

He’d worked as the garde manager in The Modern since February, handling the preparation of amuse-bouches — small appetizers — and cold food dishes.

A waiter who asked not be identified called him “a really good guy, a really hardworking guy. Everybody is so sad.”

Yang’s family said he’d gotten his prized phone in October and that it was his first iPhone. He could often be seen wearing his earbud headphones, which his family speculated might have been why he was targeted.

He was still wearing them when emergency workers arrived yesterday, the witness said.