Mohammed Zaman denies manslaughter by gross negligence, perverting the course of justice and six food safety offences in relation to the death of Paul Wilson.
"Zaman received numerous warnings that he was putting his customers' health, and potentially their lives, at risk.
Tragically for Paul Wilson, Mohammed Zaman took none of those opportunities and ignored all of the warnings he was given," prosecutor Richard Wright told Teesside Crown Court in North Yorkshire.
Zaman, 53 owns a restaurant called Indian Garden, a popular trend among Bangladeshi-origin restaurateurs to cash in on the popularity of Indian food in the UK.
Wilson, 38, was found dead at his home in Helperby, North Yorkshire, after buying a takeaway containing peanuts from Indian Garden in January 2014. He had reportedly told staff at the restaurant, in Easingwold, that his meal must be nut-free.
"An analysis of the curry recovered from the plate in the kitchen of Paul Wilson's home also demonstrated that peanut had killed him. Less than three gram of the sauce from the curry would have been sufficient to give rise to the level of peanut in the stomach," the prosecution claims.
The court was told that a week before Wilson's death, a UK trading standards officer found evidence of peanuts in a meal she had been told was peanut-free and discovered a box labelled blanched ground peanut in the kitchen of Jaipur Spice restaurant in Easingwold, North Yorkshire, another one owned by Zaman.
The jury was told that Zaman had been employing illegal workers in his takeaway and substituted almond powder with cheaper ground nut mix, which contained peanuts, as a way of cutting costs.
Zaman denies contravening EU food safety regulations and selling food not of the substance demanded, falsely describing food on a menu, and contravening food safety regulations by placing food described as nut-free on the market that was unsafe for nut allergy sufferers.
The trial is expected to last around three weeks.