One of Hong Kong’s most notorious killers — an American expat dubbed the “Milkshake Murderer”– was back in court this week with a bid to get her life sentence reduced.

Nancy Kissel earned her nickname in 2003, when she killed hubby Robert Kissel, a senior executive for Merrill Lynch, in their Hong Kong apartment — bludgeoning him to death after serving him a strawberry milkshake spiked with sedatives.

After a dramatic, well-publicized trial, Kissel, now 51, was convicted of murder in 2005 and sentenced to life in prison at Hong Kong’s maximum security Tai Lam Centre for Women.

On Wednesday, Kissel’s attorney filed a writ to the city’s high court accusing the government department that periodically reviews sentences of long-time prisoners of “wrongly” refusing to whittle down her sentence when it rejected her appeal in April 2014.

“Given…the applicant’s demonstration of remorse and repentance, the respondent acted unreasonably,” the writ states — a reference to the city’s Long Term Prison Sentences Review Board.

The writ insisted that it was “highly unlikely” Kissel would commit another crime and requested that she be transferred to the US, where the likelihood of a reduced sentence is much greater.

“The applicant is a foreign prisoner who is likely to be deported upon completion of any converted determinate sentence so that she and her family…have some idea as to what the future holds,” the court documents allege.

It’s unclear when a decision on the writ will come down, but a review board offers recommendations to Hong Kong’s chief executive regarding the release of any inmate before the end of his or her sentence.

The Michigan-born mom’s marriage to Robert Kissel, 50, began to deteriorate in mid-2003 when she periodically made trips back to their Vermont home to have an affair with a twice-married electrician, who had done work in their house, it emerged during the trial.

Robert became suspicious and hired a private investigator to keep an eye on his wife and secretly download spyware on her computer.

Tensions arose between the couple and it all came to a head on the night of Nov. 2, 2003, when Kissel had their six-year-old daughter give Robert the drug-laced drink, knocking him out, officials said.

Kissel then grabbed an eight pound metal statuette, and clubbed her husband to death, then rolled up his corpse in a carpet and dumped it in the storage room of their luxury apartment complex.

Police quickly put the pieces together and arrested Kissel, who claimed her husband had been sexually assaulting her for years and that he was a workaholic, alcoholic and cocaine addict.

During her 2005 murder trial, Kissel admitted that she killed her husband, but claimed that it was in self -defense during an argument over their looming divorce.

Prosecutors argued that Kissel stood to gain up to $18 million from the death of her rich husband, charging that she planned to elope with the Vermont electrician with whom she was carrying on the affair.

But, in February 2010, Hong Kong’s top court overturned her conviction because of legal errors in the trial.

Kissel received a new hearing, but was again found guilty in 2011 and then lost her appeal in 2014.