The Familiar by Leigh Bardugo

In a shabby house, on a shabby street, in the new capital of Madrid, Luzia Cotado uses scraps of magic to get through her days of endless toil as a scullion. But when her scheming mistress discovers that the lump of a servant cowering in the kitchen is actually hiding a talent for little miracles, she demands Luzia use those gifts to better the family’s social position.