The recipe is online here but essentially it's a stew of squash, green beans, sweetcorn and tinned beans (we usually use black-eyed or pinto but any will do), in an onion, garlic and stock base, with smoked paprika and oregano plus a bay leaf. My only amendment to the recipe is, if I'm cooking on the hob, the usual pre-cooking of the peeled and chopped squash (I microwave it on high for 8-9 minutes while I do the onions and garlic) which ensures it's nice and soft in a reasonable cooking time on the hob. Nothing worse than being all ready for a comforting stew and finding hard chunks of squash that need more cooking :(
Slow cooker: it's fine after about 5 hours on high, depending on the squash.
I find it really benefits from plenty of herbs and black pepper, but the combination of soft squash and beans, and crunchy greens and sweetcorn, is great. It's a good winter warmer and goes well with dumplings on top!
When out of both green beans and sweetcorn I added (frozen, shelled) edamame. They keep their texture a bit more when slow cooking. A good squeeze of tomato puree and a dash of cumin also work well.