If the employer offers it, I try to delve into a related topic to work as I can. Deadlines and commitments matter, so I have to know how much time I can spare. If I'm writing a report, and I realize that I don't quite understand something related, I try to set a slice of time to learn a bit more (delve into BOL, read articles, crack a book). For example, maybe I'm working with dates and I realize that I don't quite understand datetime2 v datetimeoffset. I might spend 30 minutes doing some learning here, not solving my problem, but working more to expand my knowledge. I likely won't learn what I want, but I can stop, go back to the report, and then try to take some time later. I've often taken time between tasks (finish one, break before a second), to do a little learning. It takes some discipline and focus to learn instead of going to chat with co-workers. However, you can slowly increase your knowledge.

The other way for me is to ask if I can build a POC on something. So I might take some time (30-60min a day) to work on duplicating some aspect of our application in another platform. Today that might be Azure or AWS, but in the past I've taken a RDBMS queue and played with messaging (SOA). That might be me spending 3-4 hours a week going through a course, book, or sample app.

Ultimately, I've found that I need to actually burn some personal time here. I need to treat some of my personal life as career development. Treat it like I've enrolled in a college course and get my family to buy into the need to spend a few hours a week learning.