The Mormon mom accused of killing her husband before writing a book about grief allegedly threw a massive party at her brand new $2 million home the day after he died, according to a report.

Kouri Richins, 33, invited friends to the 10-acre property for drinking and celebrating March 4, 2022 — just hours after she allegedly slipped her husband, 39-year-old Eric Richins, a lethal dose of fentanyl, court documents obtained by the Daily Mail show.

The party toasted Richins for closing in on the 22,000-square-foot unfinished home in Heber City earlier that same day.

It was a property she had dreamed of flipping, but for which her husband refused to pay the hefty price tag.

The two had argued over the home — rumored by locals to be a cursed money pit — in the weeks leading up to his demise.

Though his body was found at 3 a.m. on March 4, a day after the poisoning, it wasn’t clear if the party goers knew he was dead.

Prosecutors believe the Utah mother of three poisoned Eric in an attempt to get money from his life insurance policy the same day he told her they would not be buying the mansion and that he was cutting her out of his will.

Richins had tried to name herself the sole beneficiary on Eric’s policy, but he had changed it back to his sister’s name without telling his wife.

Richins allegedly fixed Eric a Moscow Mule later that night that was laced with roughly five times the lethal dose of fentanyl.

When police arrived, she claimed she and Eric had been celebrating plans to purchase the home before she’d gone to sleep in one of their kids’ rooms and woke to find her husband dead.

The day of the party, Eric’s sisters reportedly went to the couple’s home base in Kamas just outside Park City and “began threatening and verbally accosting Kouri.”

Richins put the mansion back on the market just two weeks later, trying to more than double her money by flipping it for nearly $5 million.

It is currently under contract for $3.75 million.

In the following year, Richins wrote a children’s book, “Are You With Me?” along with her three children which helped them deal with the loss of their father.

Eric had reportedly raised concerns that Richins had tried to kill him on at least two other occasions — including on Valentine’s Day less than three weeks before his death.

He had warned his family that “if anything happened to him she was to blame,” according to court records.

Eric also “had reason to believe” Richins was carrying out an affair throughout their marriage, his family representatives have said.

The slain husband stayed with Richins despite his numerous suspicions to spare their three sons from growing up in a broken home.

Police later unearthed Richins’ alleged connection to an accused drug dealer who admitted to selling her fentanyl pills on multiple occasions.

The widow is charged with first-degree aggravated murder and multiple counts of second-degree possession of a controlled substance with intent to distribute, records show.