For Mali, the new buzz book is Michael Gomez, African Dominion (about the Sudanic empires generally, published this year). Start there, and have a look at the New York Review of Books piece that includes a discussion of it (very recent, like a few weeks ago) and, if you have access, the American Historical Review roundtable that came out about a month or so ago.

The issue of Asante depends on when and what askpect you're talking about; Bob Edgerton's 2002 The Fall of the Asante Empire is one, but anything Ivor Wilks has done is valuable, although a few years older. More recent work tends to dive into Asante and Akan society in parts, for example Sara Berry on property and power or Jean Allman on Asante nationalism in the independence era after WWII. There's a book on Nkorana, one of the neighboring non-Asante forest states, from just a few years ago by Kwabena Adu-Boahen, but I'm not sure it is accessible being a dissertation as it is.

Kwasi Konadu, whose work I generally like a lot, does have recent readers and "history through documents" series, and he's a specialist on Akan history (including Asante, which is an Akan confederation). The Akan People: A Documentary History (2017) is the one I'd recommend, because he melds internal and external accounts of the overall history of the region deftly.

In any case, searching on "Ashanti" will generally (but not universally!) get you less academically rigorous recent material than searching on "Asante." Fluent speakers of Twi use 'Asante,' and that's how I learned it, so I'm sticking with that. Note also that "confederation" is as likely as "empire" to see use.