Beds of cover crops are visible in the background. These will be either tilled in or removed and composted before planting next spring. Meanwhile, I graze on some of them, particularly mustard greens and Swiss chard.
With only minimal protection, there are several vegetables that can be grown in winter. I'm in climate zone 6b. If you are in a colder zone, you may need to provide more serious protection, perhaps an insulated cold frame - or none at all if you're in a warmer zone.
Lettuce and snap peas are more likely to suffer from frost than mustard or kale, so be ready to cover them with reemay or similar, or grow them in plastic covered low-tunnels. Root crops like parsnips and carrots tend to store very well left right where they are - just pull them up when you need them.
Heirloom Lettuce Mix
Florida Broadleaf Mustard