Both Prince Harry and Markle's mother, Doria Ragland, were also in attendance to support Markle's first solo charity project as a royal.
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.
The book launch took place hours after it was revealed the Duchess had knocked both Jamie Oliver and JK Rowling out of the charts - before her book even went on sale.
In a speech to guests, she said the project had been a "tremendous labour of love".
Her Royal Highness first visited the kitchen in January 2018 on a private visit and had made many more visits since.
Antonio Brown Disciplined By Steelers' Coach Mike Tomlin For Skipping Practice
If the winless Pittsburgh Steelers thought the Le'Veon Bell contract situation was their biggest headache, they might be wrong. On Sunday, the team could do nothing to stop the Kansas City Chiefs as QB Patrick Mahomes lit them up time and time again.
Thomas Markle pulled out of the May's spectacular wedding ceremony at the queen's Windsor Castle home after undergoing heart surgery and amid controversy that he had staged photos with a paparazzi photographer.
"And when you know the story of the recipe, you get to know the person behind it, and that's what we're talking about in terms of coming together to really engage and talk and to be able to really celebrate what connects us rather than what divides us".
Duchess Meghan joined some women from the Hubb Community Kitchen to cook a meal of coconut chicken curry, aubergine masala and chapatis for the invited guests.
During her frequent secret visits, Meghan watched as the women came together to cook food to feed families displaced by the Grenfell Tower fire that killed more than 70 people. Meghan continued, "That's a testament to what this means to people and I'm so proud of you".
"I immediately felt connected to this community kitchen", Markle says in a promotional video for the book.
However, due to lack of funding, the women were only able to keep the facility open for two days a week.
"Meghan draws a lot of strength from her mother".