Winter cover crops/green manure

I'm curious about winter cover crops, grown to protect bare soil over winter and to improve the soil in some way as a bonus. 
I've been reading the info on https://www.sowseeds.co.uk/blogs/sow-see...een-manure and am still confused!
Does anyone here grow any of these seeds and can help me choose?
I don't fancy growing a grass seed like rye as  I hate grass and have a fear of it taking over. Same with clover.
Don't want to grow anything that needs to be dug in/turned in/mown as I'm too lazy. 
Ideally it would be something that dies in spring, or after a frost (assuming we have one). 
As a bonus, it would be edible in some way while it was growing. 

Any suggestions please?