The duchess, 37, who hosted a lunch for the women of the Hubb Community Kitchen and their families, said she had felt "immediately embraced" by the women of the kitchen who made her feel welcome on a personal level.
Joined by Ms Ragland, she helped make chapatis and turn koftas on a grill as she launched the Together cookbook in a tent. In a speech to guests, she said the project had been a 'tremendous labour of love'.
Ms Ragland embraced each of the women with a warm hug, telling them: 'It's amazing. I'm just as excited as you are. Speaking of the duchess's experience at the kitchen, she said: "She felt very much at home."
"I have just recently moved to London and I felt so immediately embraced by the women in the kitchen, by your kindness and to be in this city and be in this room and see how multi-cultural it was.
"On a personal level I feel so proud to live in a city with so much diversity. This whole country is represented by the people in the kitchen. It's pretty outstanding."
The Duchess and her mother, have not been seen in public together since the royal wedding in Windsor on May 19 and looked relaxed in each other's company.
Ms Ragland was the surprise guest at the lunchtime event on Perk's Field, outside the Palace.
Sitting in the front seat of a Land Rover Discovery with her daughter and son-in-law in the back, she stepped out and greeted the waiting guests including Hubb coordinator Zahira Ghaswala with the words: "Hi, I'm Meg's mom."
Baroness Gail Rebuck, chair of publisher Penguin Random House, told Ms Ragland she must feel "very proud" of the Duchess and her work on the cookbook. "Head over heels," she replied.
The Duchess embraced her friends at the kitchen warmly with three kisses, visibly excited at the success of the book this week and the day of the launch.
The trio, who at one point stood with their arms around one another in a line, made their way around four food stations, with the Duchess getting stuck in to help cook while her mother and husband watched on proudly.
At the first stop, Ahlam Saeid showed off an enormous bowl of green rice.
"Oh I love that," said Ms Ragland. "That was the first thing I asked about" [after learning of the cook book].
"Everyone's just hungry", said the Duchess, laughing, as she added fresh mint and olive oil to the dish.
As they made their way through tables of salad, chapatis and kofta kebabs, Ms Ragland quizzed the cooks about the ingredients, listening carefully to the herbs and spices they described.
One of the cooks promised to set food aside for the Royal couple, with the Duchess telling her: "Oh thank you, I'll take that home and have it for dinner."
She appeared to be an old hand in the kitchen, flipping chapatis confidently and turning koftas on the grill.
The Duke was careful to follow several steps behind, making small talk with guests and watching proudly as his wife took centre stage.
After guests were seated to tuck into enormous plates of food, their hosts took a moment to look around the kitchen, based in the field's clubhouse for one day only, before the Duchess made a short speech.
After lunch, the Duke, Duchess and Ms Ragland posed for a group photo with the women of the kitchen and their children before staying to chat.
Ms Ragland said: "I'm so glad I can put the face with the recipes. I'm going to tell everyone, I met her (each of the cooks)! I'm going to make everything, I'm serious."
Standing with a small group of Hubb kitchen cooks as she said goodbye, she also gave an insight into where Meghan's own beliefs have come from.
"The power of women," she said. "We make things happen. We're curious, we say yes, we show up. I'm inspired."
Meghan was reunited with the Grenfell community group who provided the dishes for Together, the fundraising publication aimed at supporting the local kitchen where the cooks meet in West London.
The idea for the book came from the Duchess after she was told, during her first private trip to the Hubb Community Kitchen in North Kensington, the facilities were only open two days a week because of a lack of funds.
The women of the Hubb Community Kitchen showcased their own personal recipes featured in the cookbook, many of which have been handed down through generations.
Guests enjoyed the home-made dishes including coconut chicken curry, aubergine masala and a range of chapatis and sharing dips, as well as caramelised plum upside-down cake, and spiced mint tea.
The Duchess joined the women as they cook the dishes and assist with the preparations, before the group and the Duke and Duchess sat to enjoy the freshly made food with their guests.
Guests also included members of the local community, representatives from Ebury Press - publishers of the book - the Al Manaar Muslim Cultural Heritage Centre, where the cooks are based, and the Royal Foundation.
On Monday, as the Duchess helped to release the new cookbook, it emerged that she made secret trips to a community mosque to cook with Grenfell Tower victims after the horrifying inferno that left 72 dead.
In her first solo project as a member of the royal family, Meghan wrote the foreword to the new book produced by cooks from the Hubb Community Kitchen, an initiative based near the site of the West London tower.
The Duchess, who said she "immediately felt connected" to the kitchen at the Al Manaar cultural centre, first visited in January and has made other secret trips to the centre to meet volunteers and learn more about their work.
One of the contributors to the book, Munira Mahmud, 34, told how Meghan donned an apron and mucked in with the cooking, including washing rice.
The Duchess says in her introduction for Together: Our Community Cookbook: "I immediately felt connected to this community kitchen; it is a place for women to laugh, grieve, cry and cook together.
"Melding cultural identities under a shared roof, it creates a space to feel a sense of normalcy - in its simplest form, the universal need to connect, nurture, and commune through food, through crisis or joy - something we can all relate to.
"Through this charitable endeavour, the proceeds will allow the kitchen to thrive and keep the global spirit of community alive."
It also emerged on Monday that two of the women who worked on the cookbook with Meghan saved the lives of seven people from different families.
MailOnline revealed Hiwot Dagnachew was on the fifth floor and stopped her two great nieces from perishing in the blaze.
She phoned their mother, who was with them on the 19th floor to warn them about the fire - giving them enough time to get out of the building.
And Munira Mahmud, 34, also managed to escape the burning building, leading the rest of her family - including her husband, his father and their two children to safety.
