Templates are helpful. If you can't find one that works for you, here are the stats that matter to achieve the system-standard rounded corner approach: The following assumes a reference document of 1024x1024 to do your primary work. First, if you use Photoshop, use this excellent script by Mike Swanson (blog dot mikeswanson dot com slash iosroundedrect) which can create a shape layer using the proper continuous corner shape. The script arguments should be 824x824 pixels dimensions with a 185.4 corner radius. Position the shape at the center of the canvas. This should result in exactly 100 pixels of gutter on all four sides. Add a drop shadow with a 28-pixel radius, a 12-pixel downward Y-axis shift (no X-axis shift), a zero spread, using pure black at 50% opacity. If desired, experiment with inner highlighting around the margins of the shape layer. Some Apple icons (like Mail) have very subtle, thin highlights to create a softly bezeled aesthetic.

This appears to be a partial answer: twitter.com/smileyborg/status/1275571597953208320?s=21

I have tried doing this and it seems that UICollectionViewCell's contentConfiguration setter is a no-op.

Please file a bug using Feedback Reporter. I do not have time to file a bug report.