A QFP package, with a square on top that has been under a laser, in an attempt to remove the original markings... However, using a light at a shallow angle allows the original markings to be seen quite clearly - it's an STM32F101.
https://assets.chaos.social/media_attachments/files/112/968/691/052/393/407/original/eaab2fa68ff0039d.jpg