The 9/11 museum’s appetite for crass commercialism will be satisfied with an 80-seat restaurant inside the memorial’s allegedly solemn grounds.

The Pavilion Cafe, run by Danny Meyer’s Union Square Events, is scheduled to open this summer inside the National September 11 Memorial & Museum — a move overlooked when museum officials took media and VIPs through the grounds last week.

The menu is expected to offer “an array of local, seasonal fare in a relaxing and comfortable environment,” according a notice in the official museum guide.

“We’re not doing this for crass or commercial reasons,” said Meyer, adding that a portion of proceeds are going back to the museum.

A rep for Union Square Events added: “We’re just trying to create a thoughtful experience and bring our hospitality [to the museum and visitors].”

The museum’s struggle with good taste was on display Tuesday night, as VIPs partied on the sacred grounds while first responders and family members of victims were turned away at the door, sources told The Post.

Before the 9/11 museum was opened to the general public on Wednesday morning, first responders and family had been been allowed inside for advance looks since last Thursday night.

But those honored visitors were turned away at the door early Tuesday evening, because only VIPs — who included former Mayor Michael Bloomberg — were allowed inside for a black-tie cocktail reception, sources said.

“To have a festive occasion on human remains, it’s repulsive, it’s repugnant,” said construction worker John Feal, a Ground Zero volunteer and activist for 9/11 first responders.

Feal said Tuesday’s closed-door, catered event could have been held at any number of spaces in the neighborhood.

“I understand the need to raise money to operate a museum,” Feal said. “But when you’re disrespecting 9/11 victims, you’ve crossed the line of being humane.”

The museum cut off the first responder and family visits Tuesday night to get ready for the general-public opening on Wednesday, according to a museum spokesman.

But the rep also confirmed that the soiree — with about 50 to 60 guests — went on, even during preparations.

“The days-long preview included 24-hour operations over that period. We had to close the museum to prepare the space for our historic public opening [Wednesday],” said museum spokesman Michael Frazier.

“While closed for these preparations, there was a very small and short gathering for donors. Those donors include Condé Nast, which is sponsoring [Wednesday’s] free admission. The small gathering was done respectfully and in recognition of our supporters, who helped to build this important institution.”

The museum’s cocktail hour took place near the “remains repository,” where 8,000 unidentified body parts are being stored.

“This is a prime example of why the remains must be removed immediately from this building — from this site of commercialism, parties, drinking, catering,” said Sally Regenhard, the mother of firefighter Christian Regenhard, who was killed on 9/11.

“This is a destination spot. This is a place they’ve turned into a social place for gatherings and festivities.”

She added: “This is the final insult and desecration of these 9/11 remains.”

Diane Horning, whose son Matthew, 26, was a Marsh & McClennan employee killed in the terror attacks, said the museum has no shame about cashing in.

“They have already explained to us that they need a gift shop to defray expenses. Now that they have set a precedent, why don’t they rent out this large space for weddings and other events?” Horning said sarcastically.

Additional reporting by Susan Edelman and Steve Cuozzo