I am surprised to find the internet has several images of Maria de Padilla.
Her daughters married John of Gaunt and Edmund of Langley and she was the grandmother (among others) of Edward, Duke of York, Constance of York and Richard of Conisbrough. (Richard of Conisbrough is known thus to historians but as Lord Richard of York in his lifetime, later Earl of Cambridge. But that's a detail.)
What is really cool about Maria is that her coat of arms included frying pans. This may be unique in heraldry, it is certainly unusual. It is apparently a pun on her surname, which I presume works in Castilian. Not three lions on a shirt - several frying pans on a shield. (Or in her case, a lozenge.)