A shiny, new skyscraper rising above Grand Central Terminal used to be the stuff of fantasy – literally.

The 2012 Hollywood hit “The Avengers”and its sequel featured Tony Stark’s eponymous Stark Tower in place of the MetLife Building – with Iron Man’s soaring penthouse getting at-level views of the Chrysler Building. Now, thanks to a deliberate, 10-month process of meetings and community engagement, such huge new buildings in Midtown East will soon become a reality – and could serve as a template for the future of zoning throughout the city.

The East Midtown Rezoning Steering Committee, chaired by Manhattan Borough President Gale Brewer and the area’s city councilman, Dan Garodnick, met every two weeks from September 2014 until June, trying to revive a rezoning proposal that had been killed by the City Council in the final days of the Bloomberg administration.

The revitalized proposal would connect public improvements to development: Developers would earn extra floor-area ratio – and therefore be able to construct taller buildings – in exchange for donating to transit improvements in the busy corridor.

Although the proposal is being prepared for delivery to the Department of City Planning by the end of summer, the policy has already been implementedin one subsection of the Midtown East study area. Builders will soon begin work on a supertall skyscraper, dubbed One Vanderbilt, at the corner of 42nd and Vanderbilt. Developer SL Green got permission to build the 1,501-foot tower by agreeing to $220 million in extensive public improvements like a pedestrian plaza between the building and Grand Central, as well as extensive improvements to the transit infrastructure that the MTA says will increase efficiency below ground and allow more subways to pass through the busy corridor.

“We all know that we need to improve our transit and infrastructure, and we should not lose the opportunity to deliver that when we are doing a significant rezoning,” Garodnick said. “We are unlocking development potential, and we are not giving it for free.”

Area stakeholders said the original Bloomberg-era proposal felt like a backroom deal, but this time things were different. The new steering committee, initiated by the de Blasio administration, was an “open-door situation,” explained Rob Byrnes, president of the East Midtown Partnership community group, who sat on the committee. He praised Brewer and Garodnick for not just bringing a proposal to the table, but for “actually being interested in what the players had to say” and adjusting and compromising as needed. The process seems to be a win for the de Blasio administration, which has been accused of failing to live up to its lofty goal of government transparency.

Brewer herself praised the participation and dedication of the members of the committee, ranging from real estate interests and business improvement districts to community groups and the Landmarks Preservation Commission. “I believe that almost 100 percent of the membership showed up every single time,” Brewer said. “There was almost no absenteeism for that entire period. People really were engaged.”

Even the Real Estate Board of New York is complimenting the proposal’s clarity in specifying expectations for developers building in the area. “I think what’s most important in this initiative is to have certainty and predictability” regarding obligations for builders, said Michael Slattery, senior vice president at REBNY. “I think one of the goals here was to create that kind of certainty from a builder’s point of view, but also there was a concern that the community understood what it was getting by way of the public realm improvement for the additional floor area that projects would be granted.”

A new building boom could also bring benefits to landmarked properties in Midtown East. Under the proposal, landmarks can sell their air rights to developers, allowing new buildings to reach higher and bringing cash into the sometimes-struggling properties.

“In the case of St. Bartholomew’s (Episcopal Church), they literally have buckets under the roof because they have so much damage to the roof,” Brewer said. “It’s a lot of money. They don’t have enough to fix it. They don’t have a big enough congregation. I want these landmarks to continue.”

Some stakeholders say the proposal’s mix of community involvement, transparency, and funding for transit and landmarks should not be limited to Midtown East, and could be a winning formula for rezoning in other Manhattan neighborhoods.

“What we did in East Midtown was very helpful both for those who appreciate new development and those who are concerned,” Brewer said. She pointed out similarities between the East Midtown process and the committee-based process City Council Speaker Melissa Mark-Viverito is leading for the rezoning of East Harlem to allow for residential development.

“We hope that East Midtown will hit the mark, and will serve as a useful precedent for other parts of the borough,” Garodnick said. “The principles can be applied in lots of different contexts. If it’s a residential rezoning and you want infrastructure improvement, you can do that.”

REBNY’s Slattery was more skeptical, saying other projects might not have the luxury of so much time to develop similar proposals.

“I don’t know how applicable the scope of this process will be,” he said. “It’s been almost a year of meetings and we’re still six to nine months away from actually having the zoning text drafted. It’s a rather lengthy process.”

He was also wary to agree that requiring developers to fund public improvements could be replicated in other neighborhoods. “Each market is different,” he said. “Obviously Midtown is a strong market and what you can do in a strong market may not be greatly applicable to other markets that may not have the same strong economic underpinnings.”

Indeed, it does not take an urban planning expert to know that East Midtown was ripe for rezoning – just a subscription to the New York Post and an eye on Steve Cuozzo’s columns describing an “exodus” of premier firms like Twitter, Citigroup and Jones Day from the Grand Central area. Even more troubling is the lack of big-time companies choosing to set up shop in the area, which conjures images of Don Draper riding the Metro-North in from Westchester rather than tech execs pulling up to the office in Teslas.

And yet, the bustling neighborhood is far from dead. One can imagine a future 15 years from now when residents of new affordable housing in Cromwell-Jerome or Sunnyside Yards commute in by subway to a gleaming new office tower on 47th and Park. And by then, those neighborhoods could have more in common with East Midtown than just subway lines, having benefitted from a new, collaborative process for rezoning projects born in the shadow of Grand Central.

Says REBNY’s Slattery: “I think what’s happened here (in Midtown East) and, I suspect, is happening with the rezonings that the de Blasio administration will be proposing in the future for housing, will have similar kinds of meetings with communities to try to understand their needs, what the concerns are, and how to move forward with a rezoning agenda that balances the equities on all sides.”