Pierce's books are mostly orderly fantasy quartets (there is a two-parter and a trilogy in there somewhere, I think...) set in two distinct fantasy lands: Tortall and Emelan. I'll focus on Tortall because there's more of it, although the Emelan books I've read are equally as good. Tortall begin with the story of Alanna, a kid with a dead mother and a distant father, who is about to be sent off to nun school to do noble lady-type stuff. Alanna doesn't want to do noble lady type stuff, and she conveniently has a brother who doesn't want to be sent off to knight school to do noble man type stuff, so she disguises herself as a boy and takes his place in knight training and he goes off to get trained in magic (which totally exists, because fantasy!) The first couple of books books deal with Alanna trying to cope with being a page and then a squire whilst disguising the fact that she's maturing into a super tiny woman and not a big burly knight-type, whilst also foiling the plans of Bad Guys and unsuccessfully fending off mutual attraction with her BFF Jonathan, who also happens to be crown prince. Spoiler alert, this is reasonably light-hearted young adult fiction, so she gets to be a knight and everybody discovers she's a woman but they mostly get over it. Also she has a magical cat that is probably actually a star constellation.
After Alanna the next quartet shifts to another character, a kid called Daine who can magically talk to all of the animals. This is weird in universe as well as in real life, so she gets to Discover Her Powers whilst also doing the whole growing up shebang, and also come to terms with having a childhood where her mother had to raise her alone despite prejudice against single mothers, and then gets murdered by bandits who Daine then kills along with a bunch of wolves she's been chatting to. Which is a bit traumatic. Also she prevents a war both against a neighbouring country and against a magic land of magic creatures, and is caretaker to a totally sweet dragon. After that, you get Keladry, who decides she also wants to be a knight and who doesn't actually have to disguise herself, but puts up with lots of prejudice from her peers and the people training them, and generally grows up to be enormous and almost unbeatable at jousting but still gets rubbish "feminine" assignments when she becomes a knight, but then it turns out they are the most important jobs and nobody else could handle them, she is just generally the best. Then there's Alanna's kid, who is a little bit annoying but ends up in the middle of a racial/colonial war and falls in love with a crow that gets to turn himself human. Basically it is all happening all the time!
I know fantasy tends to be quite a polarising genre, and reading young adult books as a grown-ass woman is also not desperately common, so a lot of people might be scratching their heads at the moment and wondering why on earth any of this is a worthwhile recommendation. The answer is this: these books are not only brilliant entertainment (rest assured, the stories happen a lot better than how I write them down here) but they also do what almost no books for young adult women do: they combine coming-of-age with wish fulfilment. We pick up with Alanna, Daine, Keladry and Aly (Alanna's kid) when they're all between around 10 and 13, and follow them through some of their most important years, both as they grow into awesome career women protecting the kingdom, and as they just generally grow into women. Alanna gets through some of the hardest parts of knight training more easily than all the bigger kids around her, only to be completely freaked out when her period comes (because dead mother, so nobody ever explained it). Daine copes with some really serious family issues and learns to respect how strong her mother was for bringing her up, whilst also coping with some really serious "oh god I can shapeshift now and I don't know how to hold on to my humanity" issues, which most teenage girls don't ever have to deal with. Unlike the first two, Kel has loving and supportive parents who remain loving and supportive (and teach her about periods), but she's grown up in a culture away from Tortall ‒ pseudo-Japan, to be specific ‒ and has to deal with being the only girl in a hostile environment, reconciling her adopted culture with her birth culture, and also with jousting with a lance twice as heavy as anybody else's because the awful boy gave her that one and she was too proud to ever give it back. They combine storylines that young women can relate to, and which humanise the troubles of young women for men who aren't used to putting themselves in the shoes of female protagonists, with plots that are pure fantasy in the best possible way. Kids can't actually be knights of a fantasy realm, but they can dream of being a girl just like them who is.
All of Pierce's Tortall women take on a patriarchal culture reasonably analagous to discrimination in the modern world, come to terms with their differing strengths and weaknesses, and achieve superhuman things with them. What's more, where the characters do have romantic interests, said romances have nothing to do with their growth (the one possible exception, Daine, has a romantic plot which could interfere with her magic teaching, but this is at the point where spoiler spoiler spoiler so she'll probably be alright...). This is not Twilight, where Edward gets to show Bella a whole new world, protect her for three and a half books, and then finally give her her own superpowers so she can protect him for a change. Nor is it the Hunger Games, which I love dearly but which is a story of a woman being brutally crushed by a world she has no agency in, but it's OK because she gets the Nice Boy at the end. All the romances are, by and large, treated as teenage romances should be: a couple last, most don't, you don't always love just one person at one time, sometimes you aren't that interested in anybody at all, and it's usually not necessary to hook up with your best friend of the opposite gender just because you're friends. Alanna's story was originally meant to be a single book for adults, so it's probably not surprising that she has a fair bit of implied sex with more than one love interest (shock!), but none of the other characters are chaste virginal types pining constantly after The One or using love triangles to motivate all of their life choices. This is refreshing.
I also like that Pierce's women don't live in a rosy genderblind world of Strong Female Characters. In fact, one of my favourite parts of Keladry's books are the Awful Teasing Boys, who continue to be awful and not accept her even after she's proven herself to the older, stuck-in-their-ways chauvinists around her. It's implied that a couple of them are just... unwell, in the same way as some women-fearing MRAs come across as unwell in the modern world. They get their comeuppance in different ways, but I love that the moral of the story isn't "kickass woman fixes everything around her!"; it's "kickass woman follows and achieves dreams and achieves love and respect from people worth achieving it from, and more would be nice, but sometimes you do just have to accept lost causes." Kel also ends up having to balance having "fun" with one of her fellow knights with sexist reactions to female promiscuity, where an older female character takes her aside and says "this is what happens, it's completely wrong, you can choose to fight it or you can modify your behaviour because of it, both will be difficult and it will suck but you should know this." It's not exactly the most inspiring message, and it may raise some feminist eyebrows that the character's choice is to be clandestine rather than organising fantasy slutwalks, because hey, she likes being a knight and she'd rather devote all her time to doing that and fighting sexist bullshit directly related to it. But, again, it drives home that these are women dealing with the practicalities of being women, however much they may suck. Not even the most dedicated feminist can fight every microaggression all the time.
So anyway that is my Sunday recommendation to you. Relive your girlhood! Or appreciate it for the first time if you didn't have one, because if I was compelled to read Catcher in the Bloody Rye and Vernon God Little as "gender neutral" coming of age books, you should be able to read the Alanna Quartet on the same terms. Tamora Pierce technically doesn't have a british publisher at the moment, which is a travesty, but I have everything she's ever written as an ebook