Donald Trump's defense team plans to call their first of several expert witnesses to the stand today.

Steven Witkoff, a New York-based real estate investor and developer, is set to testify about his expert opinion that the Trump National Doral golf course in Miami was undervalued in Trump's financial statement, despite the attorney general's claim to the contrary.

The expert report Witkoff prepared for the case also criticized the finding from the state's expert regarding the value of Trump's 40 Wall Street property.

During a 2018 roundtable on tax reform, Trump called Witkoff a "pal" who he inspired to enter the real estate industry.

"You know, people don't realize Steve started out as a lawyer -- a very good lawyer, a top lawyer in New York. And then he said, 'I'm going to go into the real estate business because I can do this, too," Trump said. "He saw me do it, and he said, 'If Trump can do it, I guess I can do it, right?'"

In a video statement posted to social media, New York Attorney General Letitia James said that the testimony of Donald Trump Jr. yesterday failed to refute any of her case against Donald Trump and his adult sons.

"After spending a full day walking through a marketing presentation to sell us all on the greatness of the Trump Organization, the defendants did not make a single point to refute the case we brought against them," James said of Trump Jr., who led off the defense's case.

Trump's eldest son, an executive VP with the family firm, functionally served as a summary witness to explain the history and notable assets of the Trump Organization, repeatedly using words like "spectacular" and "incredible" to spell out the details of Trump's properties.

James, meanwhile, drew the ire of Donald Trump for appearing to smile in court.

"A.G. Letitia James is smirking all day long from her seat in Court, as New York continues to set records in murder and other violent crimes, and businesses flee to other States," Trump wrote on Truth Social this morning, despite murders in New York City being down nearly 10% this year according to the NYPD.

The defense wrapped up the first day of its case with testimony from Donald Trump's former external tax lawyer, Sheri Dillon, who returned to the witness stand to clarify her actions related to conservation easements at Trump's properties.

Dillon previously testified during a lengthy and combative portion of the state's case.

"Welcome back. I feel like I am at a reunion -- Trump trial reunion," Judge Engoron joked when Dillon returned to the courtroom.

Dillon, explaining a potential gap in email communications about specific deals, testified that she often communicated with Eric Trump over the phone.

"If I picked up the phone and talked to him, I would know he knew what he needed to know," Dillon testified.

She also said she advised Trump's appraiser, David McArdle, that the company could add 40 additional residential units at Trump National Golf Club in New York's Westchester County by filing a new offering plan, according to an email shown in court. The clarification challenges the New York attorney general's allegation that a $101 million increase in the value of undeveloped land was based on an unfounded plan by Eric Trump to add units to the property.

During a short cross-examination, state attorney Louis Solomon attempted to challenge Dillon's authority to provide such legal information to McArdle.

"Do you know if a sponsor has a right to have an offering plan accepted for filing merely because the development meets the requirements for zoning?" Solomon asked.

"No, I do not," she responded.

Dillon concluded her testimony, and court then adjourned for the day.

Speaking outside the courthouse following his testimony for the defense, Donald Trump Jr. told ABC News that he seems to have a positive relationship with Judge Engoron.

"Perhaps there's a New York personality there, but no I think he understood," Trump Jr. said when ABC News suggested he and the judge appeared to get along. "I can't help myself even in this very serious situation. If you take yourself too seriously the world sort of sucks. You got to have a little bit of fun with it, so I did."

His relationship with the judge appears to stand in contrast to that of his father, who has accused Engoron of bias and insulted him from the witness stand.

"We had some quips in the courtroom the first time I was here," Trump Jr. said of Engoron. "Sort of gave me a fist bump on the way out. I guess I had a rather snappy response to something that was -- I can't even remember what it was right now. He said, 'That was really funny.'"

Asked by ABC News whether Trump Jr. shared his father's views about the judge being biased, the son demurred.

"Listen, I don't even know how far the gag order applies, so I don't need to do that and put myself -- I'm in enough crosshairs, guys," he said.

Donald Trump's Mar-a-Lago Club was worth more than $1.2 billion in 2021 -- roughly double the value listed in Trump's statement of financial condition -- according to defense expert Lawrence Moens.

Describing Mar-a-Lago as a castle nestled on 17.6 acres of waterfront property, Moens said he determined the value by considering nearby properties and adding the total value of the club's 500 memberships, which in 2021 cost $350,000 each.

Between 2011 and 2021, Moens' analysis found that Trump undervalued Mar-a-Lago in his statements of financial condition -- but his analysis appeared to be based on Trump being able to sell the property to an individual to use it as a private residence, which the New York attorney general says Trump is prohibited from doing based on a 2002 deed he signed that would "forever extinguish their right to develop or use the Property for any purpose other than club use."

Judge Engoron only qualified Moens as an expert on the value of residential real estate.

Moens spoke with confidence about his ability to value real estate in Palm Beach, saying that he has sold billions of dollars of real estate since his first sale as a broker in 1982. Asked if any broker has sold more Palm Beach real estate than he has, Moens replied, "They don't exist."

"I am on the front lines everyday of selling properties, and I have a pretty good handle of what is going on currently in the market," Moens said. He later added, "My numbers are usually right."

Moens also put together a seven-minute promotional video about Mar-a-Lago, which was played during his testimony. Set to relaxing music, the video included high-resolution drone shots and dramatic panning shots of the property's amenities. After the video played, Moens highlighted details such as hand-carved stones, gold decorations that cost millions to construct, and other details that required years of work from tradesmen.

"I invited the attorney general's office to come see it anytime. The offer still stands," Moens said. "I will make sure he is not there when you come," he said of Trump.

Engoron appeared attentive to Moen's testimony -- but once Moens left the courtroom, he indicated that he wasn't as concerned about Mar-a-Lago's specific value as he was about whether it was misrepresented.

"I see this case about the documents -- whether the defendants used false documents when transacting business," Engoron said. "I am not trying to figure out what the value is ... I don't necessarily consider it relevant."