Mentioning the call you'd received is the most common way, just like you already do.
In a business situation, 先程 would be more appropriate than さっき:
先程お電話頂いたBですが... This is B, I believe you called me earlier...
By adding そう, you can hint that someone else picked up the phone for you:
先程お電話を頂いたそうですが... I was informed that you called me earlier...
There are ways of directly saying "I'm returning your call", but I believe they're rarely used when talking to the original caller and more appropriate when you're describing your situation to a third party, possibly a receptionist:
(?) 折り返しお電話しております、Bと申します (To the original caller) This is B. I'm returning your call.
そちらのA様からお電話を頂いたそうで、折り返しお電話しております / 掛け直させていただいております。 (To a receptionist) I was informed that A called me. I'm returning his call.
So, that's that for business situations. I'm not aware of any other idiomatic way of putting it.
For casual situations, you can tweak the politeness of the examples above to produce informal versions for each, except 折り返し; 折り返し is just too formal.
Bだけど、さっき電話くれたよね。 It's B. Did you just call me?
さっき電話くれたって聞いたんだけど... I heard you just called me...
Aちゃんから電話があったみたいで、かけ直してます。 (To a mom) I heard A called me and I'm calling back.