The Perfect Gift by Emma Hannigan

Happy Birthday, darling girl...
When Roisin returned home from France to the seaside village of Ballyshore heartbroken, she threw herself into fulfilling her lifelong dream of running her own artisan café. Five years on, her love life is still on ice but Nourriture, her café and delicatessen, is thriving.
Then, on her thirtieth birthday, instead of the annual card from her birth mother, a woman she's never met, Roisin receives a letter signed with love, which turns her world upside down.
While she absorbs the contents of the letter, her adoptive mum Keeley grows increasingly worried that its arrival will raise questions about the secret she's been hiding from Roisin for years. A secret only one other person knows ...
As the women face truths about the past, they discover that the most precious gift of all is the love between a mother and a daughter. But will they be able to let that love light the way home?