Meghan gave a heartfelt speech in which she said she felt "privileged" to know the women of the Hubb Community Kitchen.
Ms Ragland introduced herself to guests as "Meg's mom" when she arrived at the marquee with the duke and duchess, and said she was "head over heels" with pride. She wrote the book's forward.
"I'd just recently moved to London and I felt so immediately embraced by the women in the kitchen by your warmth and your kindness".
The duchess wrote the foreword for Together, which is in bookshops from Thursday but has been available to order online for a few days.
Don't blame Neymar, PSG players all guilty - Thiago Silva
"That is good that it is not like that now and that is because of a year ago ". He was in the best shape physically since I've known him.
There was a large range on the menu, including coconut chicken curry, aubergine masala and a range of chapatis and sharing dips. Proceeds from the book will help enable the kitchen to operate seven days a week, rather than just two, and help expand its community reach. "It's 12 countries represented in this one group of women-it's pretty outstanding", she warmly told the crowd.
Markle's participation includes the support of the Royal Foundation, as well as the name recognition that comes with her face on the cover.
"Working on this project for the past nine months has been a tremendous labor of love. Melding cultural identities under a shared roof. 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".
They called their project Hubb, the Arabic word for love, and since January - Meghan has been visiting and cooking with them.
"We cook the recipes we've grown up with; there's no stress, and the recipes always work because they have been made so many times - it's proper comfort food". Meghan continued, "That's a testament to what this means to people and I'm so proud of you".