I have seen dairy free ice cream type recipes using frozen banana and made some yesterday. My blender is not particularly strong and it did struggle with the frozen banana pieces. The result was tasty but lumpy.
All the recipes I have seen say to freeze first and then blend. Is there any reason I can't do it the other way round?
I’m not sure if I could see it working the other way - I imagine it would just freeze into a solid lump of mashed banana. I’ve found that when I do it, the smaller the frozen pieces are, the fewer lumps I end up with. Perhaps try breaking your banana into smaller pieces before freezing?
Also, if you add a bit of cocoa power you an make amazing chocolate/banana “ice cream”.