It’s a picture-perfect summer’s day at the Blue Hill restaurant at Stone Barns, a bucolic foodie mecca about an hour’s drive from Manhattan in Westchester County. Couples and families take advantage of the weather to stroll about the sprawling grounds of the former Rockefeller estate. But over in the garden, the buzz isn’t about the luscious fresh produce grown on the property and used in seasonal menus. Instead, broadcast outlets are awaiting a substantial slice of Hollywood’s finest, in the form of Meryl Streep, Amy Adams and filmmaker Nora Ephron (Sleepless in Seattle, You’ve Got Mail), as they promote their own summer dish, Julie & Julia, which opens Aug. 7. It’s a tale of two cooks from different eras whose lives intertwine in surprising ways. First, there is Julia Child (Streep, whose sing-song vocal inflections evolve into near arias) in postwar Paris as she indulges her passion for food by taking classes at Le Cordon Bleu – a little more than a decade before her reign as America’s queen of French cuisine began.

Meanwhile, Julie Powell (Adams, pricklier than usual and with a pixie haircut) is the Queens cubicle dweller who in 2002 decided to plow through all 524 recipes in Child’s bible, Mastering the Art of French Cooking, in a single year and blogged about her efforts. Sharing screen time is a bounty of butter-laden delights, often glistening with high fat content, from gooey chocolate cake to decadent lobster thermidor. Today, however, the main course consists of the two women in front of the camera and the one behind it. Having just enjoyed lunch, the co-stars from last year’s Doubt— who never shared a scene together during the making of Julie & Julia— and their director are hungry to talk as they settle around a massive white couch inside one of the estate’s picturesque barns. Adams, 34, sits as primly as her Enchanted princess in a purplish jewel-tone top, black cropped pants and perilous heels. Meanwhile, Streep, 60, an empire-waisted vision in lavender, and Ephron, 68, an urban sophisticate in silver and black, take turns being hostess.

The three-time Oscar-nominated screenwriter also known for her epicurean skills – she whipped up the fake orgasm in When Harry Met Sally…— makes sure everyone has beverages at their disposal, while the 15-time Oscar-nominated actress tries to increase the comfort level of her interview mates. “Maybe I will get the director a pillow, like the suck-up I am,” Streep says before fetching a cushion. Usually, there is some sort of a recipe behind any major enterprise, and a movie – especially an obvious grab at the female market during the bombastically male-oriented blockbuster period – can benefit from one, too. Here’s how Ephron and her stars conspired to bring down the boy wizards, macho robots and commando rodents of summer.

Step 1. Recruit a master chef

Hard to imagine anyone else but Ephron, who knows her way around both a kitchen and an editing booth, would possess the finesse to properly serve Julie & Julia on the big screen. Who else would attempt to transform the struggle to create the perfect aspic or poached egg into something as gripping as a rescue at sea in an action thriller. “I promise you, someone else might have done it,” the filmmaker says. “But the whole time I was doing it, I was thinking, ‘Thank God I get to make this movie.’ ” “You have such an understanding of these worlds,” Adams says. Could a man have managed as well with the subject? “Oh, you never know,” Ephron says. “He wouldn’t have been interested to the same degree,” Streep suggests. “I’ve always said this is a movie where not a whole lot happens. Yet, that’s what life is.”

Step 2. Find the perfect setting

Julie & Julia is many things. A portrait of two women determined to fulfill their destiny. An ode to the pleasures of married life as both husbands offer nearly unconditional support. A feast of fine wining and dining where a mere chunk of cheese can cause spasms of ecstasy. But at least in the portions where Streep’s Child swoons over the delights of Parisian life, from the fragrant food markets to the romantic eateries to the splendid twinkling views, it also is a valentine to the City of Lights. The film’s main competition on opening day? G.I. Joe: The Rise of Cobra, whose boy-toy-inspired mayhem includes the annihilation of the Eiffel Tower. “It’s perfect,” Ephron says of the juxtaposition between tribute and tear-down. As for timing, she isn’t sure anymore whose idea it was to come out in the summer. “I know it wasn’t mine,” Streep says, “since I really felt this film, which had a love affair with boeuf bourguignon, should come out in winter.” But since the actress is on a hot-weather box-office streak after last year’s Mamma Mia! and 2006’s The Devil Wears Prada, there is a certain logic behind the decision. Especially, as Ephron notes, “Meryl is the reason the film got made, because she wanted to be in it.”

Step 3. Add seasoned acting

With her cheerleader good looks, Adams often can’t help but exude a natural sweetness and innate goodness on-screen. But she had to be much more obstinate and self-centered as Powell becomes increasingly absorbed in her demanding project. “Nora was great about challenging me to bring out that strength, that vulnerability and that intelligence, all the things she was at that time of her life,” says the actress, a two-time Oscar nominee. “That confusion and frustration over wanting more and not having it within your reach.” The meltdown tantrums caused by cooking catastrophes weren’t that difficult, however. “Gee, I don’t know where I came up with any of that, seeing as I don’t behave like that at all,” Adams says with a sly grin. “My fiancé could not stop laughing through most of my breakdowns and I thought, ‘Well, I think that indicates something.’ ” Streep, on the other hand, had to bring to life the towering 6-foot-2 icon – a familiar figure in most family rooms, thanks to her PBS cooking shows – without resorting to an impersonation. “It’s almost like you don’t know if you know her or Dan Aykroyd’s version of her,” she says, referring to the infamous SNL skit that pops up in the movie. “I gave myself an out. I thought, ‘I can just be Julie’s idealized Julia Child.’ ” Then there is that distinctive voice. “It’s like what I love to do,” the accent specialist says, shrugging. “So that wasn’t so hard.”

Step 4. Toss in a trend

Seven years ago, Powell was a blogging pioneer. Nowadays, it seems everyone is doing it. Everyone except Adams and Streep. “I’m too self-conscious about my writing,” Adams says. “It would take me a day to come up with anything that was suitable for anyone to read. Then I would go back, read it again to readjust, and then I would go back again.” Turning to Ephron, she says, “You actually made me write. You had me cook a recipe and write what would be a blog about it. I was paralyzed with fear. I can’t even keep a journal. I’ve never read anything that I’ve said and thought, ‘That was really worth saying. I’m so glad that that is out in public and I’ve shared that piece of myself with humanity.’ ” Says Streep, with some amusement: “I have read things I’ve said from 20 years ago and thought, ‘That’s (bleeping) great. Where did I get that idea from?’ ” That doesn’t mean she is pro-blog. “I can’t even get to correspond with the people I love – and then to broadcast to the people I don’t even know? I feel like I’m always coming up short in the personal department just with individual responses to individual people.” Ephron has found an occasional blog outlet on The Huffington Post. “The great thing is that it is mostly political,” she says. “Until Obama got elected, I had many political thoughts. Now I’m just confused.” But forget about Twitter. Says Ephron: “Let’s just cross our fingers and hope it goes away.”

Step 5. Don’t fear the butter

If Julie & Julia accomplishes anything, it might just remind everybody that before there were those plates of dipping oil served in restaurants and Rachael Ray’s EVOO, there was butter, now a demonized dairy product thanks to its fat content. “I just do not get that at all,” Ephron says. After all, Child cooked with butter all the time, and she and her husband, Paul, both lived into their 90s. “And they drank like fish,” she says. “I don’t believe that anything has to do with what you eat, if you don’t overeat. All these people who think they can cut down on their cholesterol by eating those awful egg-white omelets. There’s something I really hate. It is simply not going to make any difference if you have a couple egg yolks in your omelet.” A publicist steps in and halts the conversation like an abrupt kitchen timer going off. The ladies are due elsewhere and must move on. Child always knew what to say at moments like this. “Bon appétit!”