The Hollow Boathouse (The Anouka Chronicles)

Rosa's world seems ordinary until one day she falls for the charms of a cantankerous boy who pulls her deeper into danger. But Rosa, she's used to her witchety-Mum and deaf old Dad who bakes eggs to the ceiling. Then there's Angharad, the miniscule school witch who Rosa despises.
Maybe life at Gheptun's School of the Black Arts & Gastronomy is more than simply winning at cookery? Perhaps following a pre-destined set of rules is the only way to survive? Or is Rosa in too deep this time?