The Stories Grandma Forgot (and How I Found Them) by Nadine Aisha Jassat
 
Twelve-year-old Nyla's dad died when she was four, or that's what she's been told. So when Grandma Farida insists she saw him in the supermarket, Nyla wonders if she is 'time-travelling' again - the phrase she uses when Grandma forgets.

But when Grandma asks Nyla to find her dad and bring him home, Nyla promises that she will.

As Nyla sets out on her journey, she hopes that uncovering the past will help her to understand the mystery at the heart of her family... and to work out who she is.